Using the Accessible Graphing Calculator

By
Susan A. Osterhaus

Locating AGC files under Programs
- AGC, Magnification, and Use with Screen Readers
- Getting Started
- User Manual
Registration Screen
- Press the Continue Button, assuming your AGC is not registered
Controlling Sound and Screen Enlargement
- Useful beginning keystrokes:
  - F7 — Enlarge the AGC screen
  - F8 — Decrease the size of the AGC screen
  - Arrow left from Calculator Tab Page to Speech Tab Page (You may reach any other tab page by arrowing when you are in a Tab Page heading or by selecting the desired page from the Options menu with ALT-o)
  - ALT-s — toggles speech off and on
  - CTRL-r — reads the item that has focus except in menus
Speech Tab Page Recommended Settings (Move among items with TAB or SHIFT-TAB to move backward.)
- Sound Effects (checked)
- Allow Self-Voicing (checked)
- Voices - Arrow among voices VERY SLOWLY or program may crash. Suggestion: Select Mary, Mike, or Sam.
- Speech rate slider - adjust with arrows - start slow
- Speech pitch slider - adjust with arrows - around 65 initially
- Speech volume slider - find your comfort zone
- Continue to TAB past the bottom buttons and you will return to the Speech Tab Page
Wave Tab Page Recommended Settings (Left arrow from Speech Tab Page. Tab among these items or SHIFT-TAB to move in the opposite direction.)
- Data Set Volume - set at 50
- Play Y axis tick marks - unchecked
- Tick Mark Volume slider - set at 50
- Play noise below Y threshold (checked - check or uncheck with space bar)
- Y threshold value - set to 0
- Wave file length slider - set at 10
- Wave type - set to stereo and the sound will pan from the left (minimum x) to the right (maximum x) speaker when the graph is played
- Minimum Frequency Slider - set at 200
- Maximum Frequency Slider - set at 2500
- Auto-Speak Coordinates – check if you like the option of hearing coordinates at each step (unfortunately not voiced)
- Return to the Wave Tab Page
Settings for Visual and Audio Graphing
- Plot Tab Page Recommended Settings(Left arrow from Wave Tab Page. Tab among these items or SHIFT-TAB to move in the opposite direction.)
  - Source (use arrows to move among various choices) set to Data Set 1.
  - X min — set at -10 (to delete, highlight with CTRL-a and then press the DEL key)
  - X max — set at 10
  - Number of Points to Plot — set to 500 (Don't set higher than 1000.)
  - Y min — ignore
  - Y max — ignore
  - Autoscale y-axis - checked. (If you choose to uncheck this box, you must set Y min and Y max above. The autoscale option produces a nicer sounding audiowave. However, many graphing problems will require that the Y min and Y max be set manually.)
  - Draw data points - unchecked (I PREFER checked)
  - Draw line through data - checked
  - Draw error bars - unchecked
  - Show x-axis - checked
  - Show y axis - checked
  - Show x axis labels - checked
  - Show y-axis labels - checked
  - Plot frame - set to tick marks or grid lines
  - Plot data derivative – UNCHECKED. This is the last item on the Plot Tab page, even though it is listed near the top. Return to the Plot Tab page.
Data Set 1 (arrow up from Plot Tab page)
- Tab to Expression 1 edit box.
- Delete any characters in this box. (If the data table contains a data set, remove it by typing “clear” (without the quotation marks) and pressing ENTER. Then delete the word “clear.”)
- Example 1: Type a single x.
- Press ENTER or F4 to calculate your data table. (Using F4 requires that the source be set to Data Set 1. It's safer to use ENTER. You will hear a short tone when the computation is finished.)
- Display the graph on screen with F3.
- Play the audio graph by pressing F5.
- You should see and hear a straight line starting in quadrant 3, passing through (0,0), and ending in quadrant 1. You should hear some static while the line is below the x-axis (when y < 0), and none when the line passes through (0,0) and goes above the x-axis. You should hear the line rise from left to right, and if you have stereo speakers, you will notice the tone going from the left speaker to the right speaker.
Data Set 2 (Press CTRL F3 - hides the graph. Shift Tab to get to the Data Set 1 Tab. Then arrow to the right to find the Data Set 2 Tab.)
- Tab to Expression 2 edit box.
- Delete any characters in this box and any entries in the data table.
- Example 2: Type x^2.
- Press ENTER or F4 to calculate your data table. (Using F4 requires that the source be set to Data Set 1. It's MUCH EASIER to use ENTER. You will hear a short tone when the computation is finished.)
- Display the graph on screen with F3.
- Play the audio graph by pressing F5.
Data Set 2 (Let's make changes!)
- Example 3: Move to the end of the expression x^2 with the END key and type -10.
- Press ENTER
- Display the graph on screen with F3.
- Play the audio graph by pressing F5.
- Note the differences and similarities to x^2.
- Press ALT-PgDn and the tone graph will display the minimum.
- Read the values of x and y by pressing ALT-x to voice the x value and ALT-y to voice the y value.
Data Set 2 (Let's go crazy.)
- Press CTRL F3 to hide the graph.
- Tab to Expression 2 edit box.
- Delete any characters in this box. (Since you have numbers in your data table, you will need to type the word “clear” in the expression box and hit enter. Then delete the word “clear.”)
- Example 4: x*sin(x)
- Press ENTER
- Display the graph on screen with F3.
- Play the audio graph by pressing F5.
- Press ALT-PgDn several times to display all the relative minimums and ALT-PgUp to display all the maximums.
- Press ALT-0 several times to find all the zeros (or x-intercepts).
Printing our Graphs.
- Use the combined x and x*sin(x) graphs.
- Enter CTRL P.
- Compose a print graph with print font. Change all settings to your requirements.
- Compose a print graph with braille font. Change all settings to your requirements.
- Compose a TIGER braille graph with braille font.
Show Various Graphs created on the AGC.
Matrix Tab Page
- Enter the following two matrices into the edit box. [1,1,1;2,2,2]*[2,3;2,3;2,3] and press Enter.
- The results are now displayed after evaluation; namely, [6,9;12,18]
- Matrices may be added, subtracted, and multiplied. A square matrix may be inverted with the inv function. The determinant of a square matrix may be obtained with the det function.
Entering Data
- To plot individual points, go to Data Set 1 Expression Box (not available in Data Set 2).
- Tab to enter the table.
- Type first x value in the x column, press ENTER.
- Type first y value in the y column, press ENTER.
- Continue entering all of your data points. (You must enter a minimum of three points.)
- Enter SHIFT-TAB to return to the Expression Box.
- Press ENTER, and your database is set.

Plotting a Linear Function

Enter the following data table as outlined above.

x	1	2	3	4
y	2	4	6	8

Display the graph using F3.
Tab twice to reach the Statistical Description of Data Set button. Then press ENTER.
By using the UP and DOWN ARROW keys in this window, you can scroll through the listed statistical information. The statistical listing includes the number of data points, sum, mean, and standard and sample deviations for both the X and Y data values.
In addition, there is information obtained from regression analysis of the data. Regression is used to fit a line or curve through a set of data points using a least squares fit. The type of regression for data analysis is chosen from a separate list located below the data window. Types of regression analysis are Linear, Exponential, Logarithmic, Power, Hyperbolic, and two Rational functions. The equation used for the regression is listed along with the name. To change the method of analysis, TAB to the Mode field and use the UP and DOWN ARROW keys. The statistical information is automatically updated in the data display area.
The default mode is linear, so we can immediately find the equation fitting our data points: y = 2x .
By pressing TAB once more you will reach the first of two boxes for entering a test x or y data point. Typing a test value into one of the boxes and pressing ENTER will change the focus to display the value for the other coordinate. The value is calculated using information obtained from the chosen type of regression analysis.
Enter –10 in the y prime box, and it will tell you the corresponding x value of –5.

Plotting a Quadratic Function

Enter the following data table as outlined above.

x	1	2	3	4
y	1	4	9	16

Display the graph using F3.
TAB twice to reach the Statistical Description of Data Set button. Then press ENTER.
TAB once to enter Regression Mode list. Arrow down until you reach the Power Regression Mode. (Note: The Power Regression Mode requires that you only enter values of x and y greater than 0.)
SHIFT-TAB to return to the data display area.
Determine that the equation fitting our data is y = x^2 .
TAB until you reach the x prime box. Enter –2, and it will tell you the corresponding y value of 4.

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Last Revision: March 24, 2005