# Equation Grapher

Enter an Equation using the variables x and/or y and an =, press Go and wait:

 View Larger

## Description

It can plot an equation where x and y are related somehow (not just y=...), like these:

### Examples:

• x^2+y^2=9 (an equation of a circle with a radius of 3)
• sin(x)+cos(y)=0.5
• 2x-3y=1
• cos(x^2)=y
• (x-3)(x+3)=y^2
• y=x^2

If you don't include an equal sign, it will assume you mean "=0"

It has not been well tested, so have fun with it, but don't trust it.

If it gives you problems, let me know.

Note: it takes a few seconds to finish, because it has to calculate every pixel.

If you just want to graph a function in "y=..." style you may prefer Function Grapher and Calculator

## Zooming

To zoom into an area, select an area with the mouse (click, hold down and drag, then release). The area you selected will be the new bounds.

If you just click-and-release (without creating a rectangle), then the spot you clicked on will be the new center

You can zoom out using the Out 2X or Out 10x button.

To reset the zoom to the original bounds click on the Reset button.

## Important Note: Extra Lines

There will sometimes be lines drawn where they really shouldn't be, because you are asking the graph to draw impossible things.

### Example: 1/(x-1)

1/(x-1) is undefined at x=1 (because you would be dividing by zero). The vertical line should not be there, but the program does not know any better.

Another example is the tan() function. You may discover more, so just be careful.

## Known Bug

There are some equations it cannot plot at all. To find any point the program looks for where the equation changes sign ... this works nearly all the time except for equations like (x-y)2=0 which is always positive, or zero. Note: If you change the equation to (x-y)2=0.1 it works nicely

I am trying to think of how to fix this! Contact me if you have an idea.

## All Functions

### Operators

+ Addition operator Subtraction operator Multiplication operator Division operator Exponent (Power) operator

### Functions

sqrt Square Root of a value or expression. sine of a value or expression cosine of a value or expression tangent of a value or expression inverse sine (arcsine) of a value or expression inverse cosine (arccos) of a value or expression inverse tangent (arctangent) of a value or expression Hyperbolic sine (sinh) of a value or expression Hyperbolic cosine (cosh) of a value or expression Hyperbolic tangent (tanh) of a value or expression e (the Euler Constant) raised to the power of a value or expression The natural logarithm of a value or expression The base-10 logarithm of a value or expression Returns the largest (closest to positive infinity) value that is not greater than the argument and is equal to a mathematical integer. Returns the smallest (closest to negative infinity) value that is not less than the argument and is equal to a mathematical integer. Absolute value (distance from zero) of a value or expression Sign (+1 or -1) of a value or expression

### Constants

pi The constant π (3.141592654...) Euler's number (2.71828...), the base for the natural logarithm