##### How to use
Enter a function f (x) into the text input field marked "f(x)=".

Example: f (x)=x2

Click the "Graph" button (this button also refreshes the graph).

Enter a value for c.

Example: c=1

This can be done either of two ways:

• Enter the value directly into the text input field marked "c=", and click the "Graph" button.
• Click and drag the red point on the graph using the mouse -- this point takes its horizontal position from the mouse position, and follows the graph of f (x); the horizontal position gives the value of c.
Enter a value for x.

Example: x=2

This can be done either of two ways:

• Enter the value directly into the text input field marked "x=", and click the "Graph" button.
• Click and drag on the graph using the mouse, anywhere except the position of the red point on the graph -- the horizontal position of the mouse, shown by the vertical blue line, gives the value of x.
To erase the graph and all input fields, click the "Clear" button.
##### Examples
Polynomial: f (x)=x2, c=1, x=2

Exponential: f (x)=ex, c=0, x=1

Trigonometric: f (x)=sin(x), c=0, x=1

##### Other Notes
The values of c and f (c) are indicated in the graph by orange lines, with the red point in the graph shown at the point (c,f (c)). The values of x and f (x) are indicated in the graph by blue lines. The table shows values of f (x) for x starting at the given value and approaching c -- in particular, the values x, c+(x-c)/2, c+(x-c)/4, etc. These values are indicated in the graph by green lines.