1. Introduction
Casvi is a Computational Algebraic System that allows the development of basic and advanced mathematical operations, 
by using the Maxima mathematical engine. Casvi allows you to perform various operations of different branches of mathematics, 
such as algebra, differential calculus, and integral calculus.

2. Modules
The Casvi system offers eight modules: 

- File
- Casvi
- Simplify
- Calculus
- Graphic
- Help 
- Algebra
- Equations 

Below are the key combinations that the user must press to enter each of the interactive menus of the Casvi system:

- To enter the File menu the user must press the key combinations Alt + a
- To enter the Casvi menu the user must press the Alt + s key combinations
- To enter the Simplify menu the user must press the key combinations Alt + d
- To enter the Calculation menu the user must press the key combinations Alt + f
- To enter the Chart menu the user must press the key combinations Alt + g
- To enter the Help menu the user must press the key combinations Alt + h
- To enter the Algebra menu the user must press the key combinations Alt + j
- To enter the Equations menu the user must press the key combinations Alt + k

The description of each module will be made below.

2.1 File Menu
This menu has the new options, open, save, print, among others. The Casvi system has the option to print in Braille format, as well as to transform 
results obtained in MathML code. To enter the file menu the user must press the key combinations Alt + a.

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu.
Each option in this menu will play an audio message for the user.

2.1.1 New
Allows the creation of plain text files (*.txt). To create a file, the user must follow the instructions below:

- Open the File menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "New" option. Press the "Enter" key.
- Enter the name of the file and press "Enter" to create it. The user will hear the message "File created". 
  All files will be created in the path: "C:\Casvi\Files\"

2.1.2 Open
Allows you to open plain text files (*.txt). To open a file, the user must follow the instructions below:

- Open the file menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Open" option. Press the "Enter" key.
- Navigate through the directory. Press the up and down arrows to scroll through the files in the directory.
- Select the file and press "Enter" to open it. The user will hear the message "uploaded file".

2.1.3 Save
It stores the data found in the text editor of the Casvi system. To save the data to a file, the user must follow the instructions below:

- Open the file menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Save" option. Press the "Enter" key.
- Navigate the confirmation screen. Press the up and down arrows to scroll through the options on this screen.
- Select "Yes" and press "Enter" to save the data. The user will hear the message "Saved   changes made". 
  All files will be saved in the path: "C:\Casvi\Files\".

2.1.4 Print
Prints the data found in the text editor of the Casvi system.

- Open the file menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Print" option. Press the "Enter" key.
- Navigate the screen containing the available printers. Press the up and down arrows to scroll through the printers installed on your computer.
- Select the printer and press "Enter" to print the data.

2.1.5 Print in Braille format
Prints the data found in the text editor of the Casvi system in Braille format. To print in Braille format, the user must follow the instructions below:

- Open the file menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the option "Print in Braille format". Press the "Enter" key.
- Navigate the screen containing the available printers. Press the up and down arrows to scroll through the printers installed on your computer.
- Select the printer and press "Enter" to print the data in Braille format.

2.1.6 Generating MathML Code
Generates in MathML code the last operation performed by the Casvi system. To generate the code, you need to follow the instructions below:

- Open the file menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the option "Generate MathML code" and press "Enter" to generate the MathML code. The user will hear the message "generated code".
- The file will be created in the path: "C:\Casvi\Arquivos\MathML\".

2.1.7 Exit
Allows you to exit the Casvi system. To exit the system, you need to follow the instructions below:

Option A
- Open the file menu. Press the "Alt + a" or "Alt + A" keys.
- Navigate through the file menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Exit Casvi" option. Press the "Enter" key.
- Navigate the confirmation screen. Press the up and down arrows to scroll through the options on this screen.
- Select "Yes" and press "Enter" to exit the Casvi system.

Option B
- In the Casvi system editor press the "Esc" key.
- Navigate the confirmation screen. Press the up and down arrows to scroll through the options on this screen.
- Select "Yes" and press "Enter" to exit the Casvi system.

2.2 Casvi Menu
This module allows you to view all the menus of the Casvi system, make general settings, delete the text editor, and delete all the data stored by the 
Casvi system. In addition, it has an option for users to know and memorize the location of each of the keys. To enter the Casvi menu you must 
press "Alt + s" or "Alt + S".

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu.
Each option in this menu will play an audio message for the user.

2.2.1 Menus
Displays all Casvi system menus. To choose a menu, the user must follow the instructions below:

- Open the Casvi menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Menus" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system modules. Press the up and down arrows to scroll through the available menus.
- Select the menu and press the "Enter" key to open it.

2.2.2 Configurations
It allows you to perform the general configuration of the Casvi system. The user has six configuration options: audio, language, speech synthesizer speed, 
significant numbers, decimal numbers, and fractional numbers. To choose the configuration option, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system configuration options. Press the up and down arrows to scroll through the available options.
- Select the configuration option and press the "Enter" key to open it.

A description of each of the configuration options will then be made.

2.2.2.1 Audio
Sets the volume level of the Casvi system. To perform this configuration, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system settings. Press the up and down arrows to scroll through the available menus.
- Select "Audio". Press the "Enter" key.
- Enter 1 for high, 2 for medium or 3 for null (enter only the number depending on the desired level). Press the "Enter" key to perform the setup. 
  The user will hear the message "Configuration executed".

2.2.2.2 Language
Sets the Casvi system language. To perform this configuration, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system settings. Press the up and down arrows to scroll through the available menus.
- Select "Language". Press the "Enter" key.
- Enter 1 for Spanish, 2 for English or 3 for Portuguese (Enter only the desired language number). Press the "Enter" key to perform the setup. 
  The user will hear the message "Configuration executed".

2.2.2.3 Rate of the speech synthesizer
Sets the speed of the speech synthesizer. To perform this configuration, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system settings. Press the up and down arrows to scroll through the available menus.
- Select "Rate of the speech synthesizer". Press the "Enter" key.
- Enter between 1 (slow) and 10 (fast). Press the "Enter" key to perform the setup. The user will hear the message "Configuration executed".

2.2.2.4 Significant numbers
Sets the significant numbers. To perform this configuration, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the configurations of the Casvi system. Press the up and down arrows to scroll through the available menus.
- Select "Significant numbers". Press the "Enter" key.
- Enter the number of significant digits. Press the "Enter" key to perform the configuration. The user will hear the message "Configuration executed".

2.2.2.5 Decimal numbers
Allows you to express fractions in decimal form. To perform this configuration, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system settings. Press the up and down arrows to scroll through the available menus.
- Select "Decimal Numbers" and press the "Enter" key. The user will hear the message "Configuration executed".

2.2.2.6 Fractional numbers
This configuration allows the system to maintain fractions when they are inserted. For example, if you enter the fraction 1/2 instead of solving and 
display the result "0.5" Casvi will keep the fraction as a result. To perform this configuration, the user must follow the instructions below:

- Open the Casvi Menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Configurations" option. Press the "Enter" key.
- Navigate the screen containing the Casvi system settings. Press the up and down arrows to scroll through the available menus.
- Select "Fractional Numbers" and press the "Enter" key. The user will hear the message "Configuration executed".

2.2.3 Clean editor
This command clears the Casvi system editor. To use this command, you must follow the instructions below:

Option A
- Open the Casvi menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Clean Editor" option and press the "Enter" key.

Option B
- In the Casvi system editor Type "clc" and press "Enter".

2.2.4 Clean everything
This command deletes all information displayed and stored by the Casvi system. To use this command, you must follow the instructions below:

Option A
- Open the Casvi menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Clean All" option and press the "Enter" key.

Option B
- In the Casvi system editor Type "clear" and press "Enter".

2.2.5 Test the keyboard
The "test the keyboard" tool allows the user to know the location of the keys on the computer keyboard. This makes it easier to learn and adapt to 
make use of the functions of the Casvi system. Pressing each key will play the corresponding audible message. To use this feature, 
you should follow the instructions below:

- Open the Casvi menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the Casvi menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Test the keyboard" option and press the "Enter" key.

2.3 Equations menu
Allows to find the roots of a polynomial, calculate the root of an expression in a certain interval, and solving a linear system of up to ten equations. To enter the equations menu must press "Alt + k" or "Alt + K.”
To navigate this interactive menu, you can use the arrow keys or press the letter with which the name of each of the available options begins 
in this menu. Each option in this menu will play an audio message for the user.

2.3.1 Solve
Find the roots of a polynomial. To perform this mathematical operation, the user must follow the instructions below:

- Open the equations menu. Press the "Alt + k" or "Alt + K" keys.
- Navigate the equations menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Resolve" option and press the "Enter" key. The user will hear the message "Type the polynomial".
- Enter the polynomial and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

If the polynomial is entered incorrectly, the user will hear the message: "Incorrect syntax".

2.3.2 Find root
The purpose of this function is to analyze the zero crosses on the axis of the abscissas of an expression; This expression must be between a closed range of 
real numbers. To perform this mathematical operation, the user must follow the instructions below:

- Open the equations menu. Press the "Alt + k" or "Alt + K" keys.
- Navigate the equations menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Calculate Root" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Enter the lower limit".
- Enter the lower limit and press "Tab". The user will hear the message "Enter the upper limit".
- Enter the upper limit and press "Tab". The user will hear the message "Type the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

If one of the parameters required by this function is entered incorrectly, the user hears the message: "Incorrect syntax".

2.3.3 Polynomial roots
Find the roots of a polynomial.

- Open the equations menu. Press the "Alt + k" or "Alt + K" keys.
- Navigate the equations menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Polynomial Roots" option and press the "Enter" key. The user will hear the message "Type the polynomial".
- Enter the polynomial and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

If the polynomial is entered incorrectly, the user will hear the message: "Incorrect syntax".

2.3.4 Resolver linear system
Solve a system of up to ten linear equations with ten unknowns. To perform this mathematical operation, the user must follow the instructions below:

- Open the equations menu. Press the "Alt + k" or "Alt + K" keys.
- Navigate through the equation’s menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Solve Linear System" option and press the "Enter" key. The user will hear the message "Enter the number of equations".
- Enter the number of equations (from 1 to 10) and press "Enter". The user will hear the message "Enter the variables".
- Enter the variables separated by commas (e.g., x, y, ...) and press "Tab" to continue. The user will hear the message "Enter equation 1".
- Enter equation 1 and press "Tab" to continue. The user will hear the message "Enter equation 2".
- Enter equation 2 and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

If one of the parameters required by this function is entered incorrectly, the user hears the message: "Incorrect syntax".

2.4 Algebra Menu
This module aims to make it easier for the user to solve mathematical problems of linear algebra. To enter the algebra menu, you must press "Alt + j" or "Alt + J".

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu.
Each option in this menu will play an audio message for the user.

2.4.1 Generate matrix
Generates an array of n rows per m columns. To use this feature, you need to follow the instructions below:

- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Generate Array" option and press the "Enter" key. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Tab". The user will hear the message "Enter the matrix element"
- Enter the matrix element and press "Enter". The user will automatically hear the result obtained. In addition, the results will be 
  presented in the Casvi system editor.

Once successfully created, the array will be stored in memory with the name designated above.

2.4.2 Enter matrix
It allows you to enter an array of up to 9 rows and up to 9 columns. Below are the instructions for entering a 2-row, 2-column array. 

- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Entered Matrix" option and press the "Enter" key. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Enter the elements of the 2x2 matrix, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will automatically listen to the entered matrix. In addition, the results 
  will be presented in the Casvi system editor.

Once entered correctly, the array will be stored in memory with the previously designated name.

2.4.3 Inverse matrix
Find the inverse of a matrix. The requirements for an array to be reversed are as follows:

- The matrix must be square.
- The determinant of the matrix must be zero.

The following are instructions for inverting a 2-row, 2-column array:

Option A
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Reverse Array" option and press the "Enter" key. The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To invert an array using option B, you must first enter an array. Below are the instructions for reversing the M matrix (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Reverse Array" option and press the "Enter" key. The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
  in the Casvi system editor.

2.4.4 Characteristic polynomial
Calculates the characteristic polynomial of a matrix. Below are the instructions for calculating the characteristic polynomial of a 2x2 matrix:

Option A
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Characteristic Polynomial" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To calculate the characteristic polynomial of a matrix using option B, it is necessary to pre-enter a matrix. Below are the instructions for calculating 
the polynomial characteristic of the M matrix (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Characteristic Polynomial" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
  in the Casvi system editor.

2.4.5 Determinant
Calculates the determinant of a matrix. Below are the instructions for calculating the determinant of a 2x2 matrix:

- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Determinant" option and press the "Enter" key. The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To calculate the determinant of a matrix using option B, you must first enter an array. Below are the instructions for calculating the 
determinant of the matrix M (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Determinant" option and press the "Enter" key. The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
  in the Casvi system editor.

2.4.6 Own values
Calculates the eigenvalues of an array. Below are the instructions:

Option A
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Own Values" option and press the "Enter" key. The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To calculate the eigenvalues of an array using option B, you must first enter an array. The following are the instructions for calculating the eigenvalues of the
matrix M (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Own Values" option and press the "Enter" key. The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
 in the Casvi system editor.

2.4.7 Eigenvectors
Calculates the automatic vectors of a matrix. Below are the instructions for calculating the eigenvectors of a 2x2 array:

Option A
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Own Vectors" option and press the "Enter" key. The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To calculate the eigenvectors of a matrix using option B, you must first enter a matrix. Below are the instructions for calculating automatic vectors 
matrix M (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Own Vectors" option and press the "Enter" key. The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
 in the Casvi system editor.

2.4.8 Attached matrix
Returns the attachment of an array. The following are the instructions for calculating the attached array of a 2x2 array:

Option A
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Attached Matrix" option and press the "Enter" key. The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To calculate the attached matrix of an array using option B, an array must be entered beforehand. Below are the instructions for calculating the attached array 
matrix M (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Attached Matrix" option and press the "Enter" key. The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
  in the Casvi system editor.

2.4.9 Transpose matrix
Returns the transposition of an array. Below are the instructions for calculating the transposition of a 2x2 array:

Option A
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Transpose Array" option and press the "Enter" key. The user will hear the message "Enter the array".
- Press the "Alt + m" or "Alt + M" keys to activate the "Enter Matrix" function. The user will hear the message "Enter the name of the array".
- Enter the name of the array and press "Tab". The user will hear the message "Enter the number of rows".
- Enter the number of lines and press "Tab". The user will hear the message "Enter the number of columns".
- Enter the number of columns and press "Enter". The user will hear the message "Type the elements of the matrix 2x2, row 1, column 1".
- Enter the first element of the array and press "Tab". The user will hear the message "row 1, column 2".
- Enter the second element of the array and press "Tab". The user will hear the message "row 2, column 1".
- Enter the third element of the array and press "Tab". The user will hear the message "row 2, column 2".
- Enter the fourth element of the array and press "Enter". The user will hear the message "Matrix entered".
- Finally, press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

To calculate the transposition of an array using option B, you must first enter an array. Below are the instructions for calculating the 
transposition of the matrix M (previously entered):

Option B
- Open the algebra menu. Press the "Alt + j" or "Alt + J" keys.
- Navigate through the algebra menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Transpose Array" option and press the "Enter" key. The user will hear the message "Enter the array".
- Enter the name of the array (in this case M) and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented 
  in the Casvi system editor.

2.5 Retail Menu
Allows the user to perform advanced mathematical operations, such as determining the LaPlace transform of a function, developing a Taylor series, or performing 
differential and integral calculus operations on a variable. To enter the calculation menu, you must press "Alt + f" or "Alt + F".

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu. 
Each option in this menu will play an audio message for the user.

2.5.1 Integrate
Calculates the integral of an expression relative to the integration variable. This integration is not defined, which means that you do not have to enter 
integration. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Integrate" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Type the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.2 Defined integration
Calculates the integration of an expression with respect to the integration variable. This integration is defined, which means that you must introduce integration limits. 
To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Integration defined" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Enter the lower limit".
- Enter the lower limit and press "Tab". The user will hear the message "enter the upper limit".
- Enter the upper limit and press "Tab". The user will hear the message "Type the expression"
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.3 Differentiate
Returns the derivative of an expression. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Differentiate" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Type the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.4 Calculate limit
Calculates the limit of an expression as the real variable "x" approaches the defined value. to perform this mathematical operation, you must follow 
the following instructions:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu
- Select the "Calculate Limit" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Enter the point".
- Enter the dot and press "Tab". The user will hear the message "Enter the address".
- Enter the address and press "Tab". The user will hear the message "Type the expression"
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.5 Get Series  
Calculate approximations of the function through a series of powers or sum of integer powers. to perform this mathematical operation, you must follow 
the following instructions:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Get series" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Enter the point".
- Enter the dot and press "Tab". The user will hear the message "Type the maximum degree".
- Enter the maximum degree and press "Tab". The user will hear the message "Type the expression"
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.6 Calculate sum
Calculates the sum of an expression or function within a range of values. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Calculate Sum" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Type from".
- Enter from where the sum calculation starts and press "Tab". The user will hear the message "Type to".
- Enter to the sum calculation is made and press "Tab". The user will hear the message "Type the expression"
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.7 Calculate product
Calculates the product of an expression or function within a range of values. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Calculate Product" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Type from".
- Type from where the sum calculation starts and press "Tab". The user will hear the message "Type to".
- Type where the sum calculation is made and press "Tab". The user will hear the message "Type the expression"
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.8 Laplace transform
Calculates the Laplace transform of an expression based on the time variable t for a new expression based on the variable at frequency s. To perform 
In this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Laplace Transform" option and press the "Enter" key. The user will hear the message "Enter the old variable".
- Enter the old variable and press "Tab". The user will hear the message "Enter the new variable".
- Enter the new variable and press "Tab". The user will hear the message "Type the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.9 Inverse transform
Calculates the inverse Laplace transform of an expression based on the variable in frequency s for a new expression based on the variable in time t. To perform 
In this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Reverse Transform" option and press the "Enter" key. The user will hear the message "Enter the old variable".
- Enter the old variable and press "Tab". The user will hear the message "Enter the new variable".
- Enter the new variable and press "Tab". The user will hear the message "Type the expression"
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.5.10 Greatest common divisor
Returns the maximum common divisor of polynomial 1 and polynomial 2. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Maximum Common Splitter " option and press the "Enter" key. The user will hear the message "Type the polynomial 1".
- Enter polynomial 1 and press "Tab". The user will hear the message "Type the polynomial 2".
- Enter polynomial 2 and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the editor 
  Casvi system.

2.5.11 Minimum common multiple 
Returns the minimum common multiple of polynomial 1 and polynomial 2. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the option "Minimum common multiple" and press the "Enter" key. The user will hear the message "Type the polynomial 1".
- Enter polynomial 1 and press "Tab". The user will hear the message "Type the polynomial 2".
- Enter polynomial 2 and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the editor 
  Casvi system.

2.5.12 Divide polynomials
It divides two input expressions (polynomials) of varying degrees. The variable you enter must be the same for both mathematical expressions. 
To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Split Polynomials" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Type the polynomial 1".
- Enter polynomial 1 and press "Tab". The user will hear the message "Type the polynomial 2".
- Enter polynomial 2 and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the editor 
  Casvi system.

2.5.13 Partial fractions
Expands the input expression into partial fractions relative to the primary variable. To perform this mathematical operation, the user must follow the instructions below:

- Open the calculation menu. Press the "Alt + f" or "Alt + F" keys.
- Navigate through the calculation menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Partial Fractions" option and press the "Enter" key. The user will hear the message "Enter the variable".
- Enter the variable and press "Tab". The user will hear the message "Type the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.6 Simplify menu
This module helps the user to simplify mathematical expressions that initially contain multiple complex terms or expressions into shorter expressions or 
simplified. Allows you to factor algebraic expressions. To enter the simplify menu you must press "Alt + d" or "Alt + D".

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu.
Each option in this menu will play an audio message for the user.

2.6.1 Simplify expression 
Evaluates an expression and returns a simplified expression. To perform this mathematical operation, the user must follow the instructions below:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Simplify Expression" option and press the "Enter" key. The user will hear the message "Enter the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the editor 
Casvi system.

2.6.2 Simplify radicals 
Simplifies expression, which can contain logarithms, exponentials, and radicals, turning it into a canonical form, meaning that all expressions 
they are reduced to a single form. To perform this mathematical operation, the user must follow the instructions below:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Simplify Radicals" option and press the "Enter" key. The user will hear the message "Enter the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.6.3 Factor expression
Factor the expression that can contain any number of variables or functions. To perform this mathematical operation, the user must follow the instructions below:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Factor Expression" option and press the "Enter" key. The user will hear the message "Type the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.6.4 Complex factoring
This function is responsible for factoring all kinds of equations that contain a complex solution. to perform this mathematical operation, you must follow 
the following instructions:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Complex Factor" option and press the "Enter" key. The user will hear the message "Enter the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.6.5 Expand Expression
Expands a factored expression. To perform this mathematical operation, the user must follow the instructions below:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Expand Expression" option and press the "Enter" key. The user will hear the message "Enter the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.6.6 Contracting logarithms
This function uses logarithmic properties to solve and simplify equations containing logarithms. to perform this mathematical operation, you must follow 
the following instructions:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the option "Hire logarithms" and press the "Enter" key. The user will hear the message "Enter the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.6.7 Trigonometric simplification
This function uses trigonometric identities to solve and simplify equations. To perform this mathematical operation, the user must follow the instructions below:

- Open the simplify menu. Press the "Alt + d" or "Alt + D" keys.
- Navigate the simplify menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Trigonometric Simplification" option and press the "Enter" key. The user will hear the message "Enter the expression".
- Enter the expression and press "Enter". The user will automatically hear the result obtained. In addition, the results will be presented in the Casvi system editor.

2.7 Graphic menu
This module focuses on the sound presentation of some mathematical functions. To enter the Graphic menu, you must press "Alt + g" or "Alt + G".

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu.
Each option in this menu will play an audio message for the user.

2.7.1 Plot 2D
Performs the sound representation of some mathematical functions. to use the 2d path function you must follow 
the following instructions:

- Open the graphic menu. Press the "Alt + s" or "Alt + S" keys.
- Navigate through the graphic menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "2D Chart" option. Press the "Enter" key.
- Navigate the screen that contains the functions for the plot. Press the up and down arrows to scroll through the available features.
- Select the function (for example, sin(x)) and press "Enter". The user will hear the sound representation of the selected function.

2.8 Help Menu
It provides the user with information about the operation of each module, submodule, and functions of this program. Here the user will find general descriptions and 
examples of the Casvi system. To enter the help menu, you must press "Alt + h" or "Alt + H".

To navigate through this interactive menu, you can use the arrow keys or press the letter with which you get the name of each of the options available in this menu.
Each option in this menu will play an audio message for the user.

2.8.1 Casvi Help
This option contains five menus: Simplify, Calculus, Graph, Algebra and Equations. Each of the menus has descriptions of each of its functions. 
To access the Casvi system help, the user must follow the instructions below:

- Open the help menu. Press the "Alt + h" or "Alt + H" keys.
- Navigate through the help menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Casvi Help" option. Press the "Enter" key.
- Explore help options. Press the up and down arrows to scroll through the available menus.
- Select the menu and press "Enter" to open it.
- Navigate through the menu functions. Press the up and down arrows to scroll through the available features.
- Select the function and press "Enter" to open it. The user will hear the description of the function.

2.8.2 Examples
It contains examples of mathematical operations that the Mejía system can perform. To access the Casvi system examples, you need to follow the instructions below:

- Open the help menu. Press the "Alt + h" or "Alt + H" keys.
- Navigate the help menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Examples" option. Press the "Enter" key.
- Explore the sample options. Press the up and down arrows to scroll through the available menus.
- Select the menu and press "Enter" to open it.
- Navigate through the menu functions. Press the up and down arrows to scroll through the available features.
- Select the function and press "Enter" to open it. The user will hear three examples of the chosen function.

2.8.3 About
Displays the casvi system information. To access this option, the user must follow the instructions below:

- Open the help menu. Press the "Alt + h" or "Alt + H" keys.
- Navigate the help menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "About" option and press the "Enter" key. The user will hear information from the Casvi system
 
2.8.4 Suggestions
Presents casvi system suggestions. To access this option, the user must follow the instructions below:

- Open the help menu. Press the "Alt + h" or "Alt + H" keys.
- Navigate the help menu. Press the up and down arrows to scroll through the options in this menu.
- Select the "Suggestions" option and press the "Enter" key. The user will listen to suggestions from the Casvi system. To change the suggestion press "Tab".

3. Special commands
These commands work with the F1 through F9 keys. Each of these keys fulfills different functions that can be applied on both the main screen and the main screen. 
screens generated from the options that each menu has. It should be noted that, having activated a special command, it is necessary to press the button 
escape "Esc", to exit and enter another command. The description of each command will be made below.

3.1 F1 Command: Reproduction
This command lets the user know what they are typing. For example, if you are in the Casvi system editor, by pressing this key, 
it will explain which line the cursor is on, providing the line number and what is written in it. In addition, it serves to know in what 
the cursor is in the Casvi system menus.

3.2 F2 Command: Arithmetic Operators
It has the menu arithmetic operators of the Casvi system.

- Sum +
- Subtract -
- Multiplication *
- Division /
- Power ^
- Factorial !

By pressing the "Enter" key on any of these operators, the selected operator will be entered into the command line where the cursor was located.

3.3 F3 Command: Mathematical Operations
There are twelve mathematical operations that are part of this menu, which are:

- Square root
- Logarithm
- Base logarithm 2
- Logarithm base 10
- Absolute value
- Breast
- Cosine
- Tangent
- Cotangent
- Secant
- Cosecant
- Exponential function

When any of these mathematical operations are selected, a window appears where the argument of the selected function must be entered;
as the case may be. Once the argument has been entered successfully, the "Enter" key should be pressed. The new expression will be added were 
the cursor was.

3.4 Command F4: Special Constants
This menu contains five special constants that can be used by the Casvi system, which are: 0, pi, and infinity, -infinity.

3.5 F5 Command: Expressions
There are expressions stored in the Casvi system. They can be edited in the console once selected. Some of the stored expressions are as follows:

- sin(x)
- cos(x)
- tan(x)
- sec(x)
- cot(x)
- x*sin(x)^2
- sin(x)*cos(x)
- x^2*cos(x)
- sec(x^3)
- log(5*x+7)
- 1/x

3.6 F6 Command: Stored Variables
This command allows you to view the variables that were stored. To use a variable by pressing the "Enter" key on one of them. 
The variable will be entered where the cursor was. To assign a value or expression to a variable, follow these steps:

- Enter the name of the variable, it can be a word or a letter, followed by the name should be written ": ".
- Then type the expression you want to assign to the variable.
- Finally, press the "enter" key to store the variable.

3.7 F7 Command: Results
Pressing this key presents a new window in which you will find all the results obtained from the operations performed by the Casvi system.

3.8 F8 Command: Transformations
Pressing this key will display a menu called Transformations, where you can select two options. the first option performs the value transformation 
in radians for degrees and the second option performs the reverse process to use it, simply press "Enter" on the transformation option you want to perform. 
Then another box will open in which the value to be entered must be entered, and then press "Enter". The result will be displayed on the screen.

3.9 Command F9: Fraction
This command allows the entry of a fraction.

3.10 Additional Commands

3.10.1 Command %
This command displays the result obtained from the last operation performed.

3.10.2 Command :
This command allows assigning a value to a variable. The name of a variable always begins with a letter and can then contain both letters and numbers.
