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Shareware Overload Trio 2
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GRMAT5.HLP
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1994-03-06
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NUMERICALLY EVALUATING A POINT
The Evaluate command in the point menu allows you to quickly find the value of
any equation you've entered at a specific point. First choose an equation from
the queue by selecting it in the equation combobox. (If you do not choose an
equation, Graphmatica will select the last one graphed for you.) Then choose
the Evaluate command from the Point menu.
You will be asked to enter a value for the selected equation's independent
variable. Any expression that evaluates to a constant is OK, including
fractions and constants. Graphmatica will calculate the value of the dependent
variable(s) at this point and display the result. For function families that
use the parameter 'a', only the starting value of 'a' will be used, since only
one result can be displayed. (Note that if an error occurs when evaluating at
the point, a message will be displayed on the bottom line regardless of the
state of the Warning Messages option.) Press any key to type in another point
to evaluate. When you want to stop evaluating points, press ESC to return to
the menu.
Set IV COMMAND
This option allows you to choose the initial-value point for an ODE
approximation using the crosshairs. You must type in or select a differential
equation in the listbox first. See the Graphing help or manual for details.
Press PgDn for help on the Coordinate Cursor.
THE COORDINATE CURSOR
If the point you're interested in is on-screen, you can use the coordinate
cursor to estimate its coordinates. Simply select the Cursor item in the Point
menu and use the arrow keys or mouse to maneuver the crosshairs over the point
in question. The coordinates of that point are displayed at the bottom of the
screen. Then press ESC to return to the menu.
If you have a mouse, the crosshairs will appear at the current position of the
mouse pointer and will respond to both the mouse and the keyboard. To exit the
coordinate cursor, click either mouse button.
When you use the keyboard to position the pointer, you will notice that it
moves about 20 pixels with each keypress. (This makes it possible to move
rapidly from one side of the screen to the other.) To move the crosshair one
pixel at a time, hold down the Ctrl key while pressing the arrow keys.
Remember that the values reported by the coordinate cursor are limited by the
resolution of your screen. At the default grid size, values may be off by 0.01
or more. For best results, you may want to zoom in on the section of the graph
you are interested in before examining specific points with the cursor.
────────────────End of Point help. Press ESC to return to menu.───────────────