Entering a function

You can enter a functional expression in any empty edit field underneath the Function heading. Enter expressions in standard (infix) notation. For example, "sin(x^2)" represents that sine value of the variable x to the power of 2.

Displaying the Graph

After entering a valid function, click on the check box next to the edit field. If the expression is syntactically correct, the graph will immediately display, otherwise an error message will be presented. After you make a modification to a function, uncheck and recheck the box to update the graph.

Setting the Graph Parameters

Click on the Set Graph button to change the graphs range and domain, grid settings, and the domain variable.

Domain	Set the minimum and maximum values for the horizontal axis, and the increment to draw grid lines.
Range	Set the minimum and maximum values for the vertical axis, and the increment to draw grid lines.
Grid Lines	Specify a value of 0.0 to not draw grid lines. Otherwise, grid lines will be drawn at the given increment.
Increments	Specify how many points to calculate. The maximum value is the number of pixels the graph is currently using horizontally. Reducing this number can speed the plotting, but it will be less accurate.
Domain Variable	This is the variable to adjust along the horizontal axis. The default value is X. You should use this variable in your functions.
Timer Variable	This is the variable that is adjusted with time. Every 1 second, 0.1 will be added to this variable and the plot redone. If the variable does not exist, the plot will not be redone. A variable cannot be removed, so to prevent redrawing of the graph, change this to a non-existent variable.

Currently, it is not possible to find the actual numeric value of a function at a arbitrary point. You can find an exact value at any point used to draw the graph, by moving the mouse over the graph. For most points, the popup will display the X and Y coordinate of the mouse. However, when you are over a point used for plotting, the popup will change to the color of the plot that matches that point, and the values will be exactly what was calculated, and shown in the form "F#(domain value) = range value."

Combining Functions

You can use the value of any other function in your function expression. To do so, you must specify the name of the variable the other function uses, and the value to use for that variable. This is specified using the syntax "variable name=value" where value is any valid expression. You identify the function using the name on its check box (f1, f2, etc.). For example:

F1	sin (x) + 2
F2	F1(x=x+1)

In this example, the graph of f2 will be the same as f1 shifted left by the value of 1. Note: both functions can use the same variable, and using F1 does not actually change the value of the variable.

At this time, only one value can be set to be used by the other function. If a function uses two variables (a domain and a time variable), you can only set one. The current value of the other variable will be used.

Using a Timer

You can use the default timer variable, T, or specify one of your own in the graph settings. When you use this variable, the plot will be recalculated approximately every 1 second, and the timer variable will be incremented by 0.1. Once you have created a function that uses the timer variable, the plot will continue to redraw until you change the timer variable to a non-existent variable. When the timer is active, the current value will be displayed in the lower-left corner of the graph. For example, the function sin (x+t) will display a sine wave, shifting slightly to the left once per second.

The timer variable is reset whenever the Graph Settings dialog is closed using the OK button.

Using Differentials

You can also use the slope value of another function. Use the apostrophe ( ' ) after the function name to use the differential value. You could set the f2 function to f1'(x=x) to show a graph of the derivative of f1.

Using Integrals

Use the tilde ( ~ ) after the name of a function to use the integral value. The integral is taken over the current graphing range, as its value is affected by the staring position (the constant C varies depending on the starting position, such that the solution at the minimum value is 0).

Available Functions and Operators

Here is a list of available operators and operations

Symbol	Operation	Example
+	Adds 2 numbers	x + y
-	Subtracts the left number from the right.	x - y
-	Negates a number. A unary minus must follow an opening parenthesis, a comma, or be the first symbol in the expression.	(-1)
*	Multiplies two numbers.	x * y
/	Divides the left number by the right.	x / y
^	The left number taken to the power of the right.	X ^ Y
!	Factorial of the number to the left.	X!
Sin	The sine of an angle in radians.	Sin((x*PI)/180) or sin x
Cos	The cosine of an angle in radians.	Cos(x/4) or cos x
Tan	The tangent of an angle in radians.	Tan (X)
Sqrt	The square root of a number.	Sqrt(100)
Abs	The absolute value.	Abs(-1)
Exp	The constant e to the power of the given number.	Exp(x)
Log	The natural log of a number.	Log(x)
Min	The minimum of two values.	Min (100,x)
Max	The maximum of two values.	Max (1,x)

Constants

The following constants can be used.

Symbol	Value	Examples
E	2.7182818284590452354	E ^ X
PI	3.14159265358979323846	Sin ((x*PI)/180)