# Graphing an equation on calculator question

1. Sep 20, 2008

### Hayman Chan

How do I graph an inverse parabola on a calculator? As in a normal parabola but opening to the left or right. Which means its X= instead of Y=.

If this is impossible(I know it is possible to use two seperate equations), is there any other way to add more "Y="s on the graphing calculator? There is only 10 at the moment, and my assignment is to use basic graph and transformations to draw pictures, on a graphing calculator. My main problem right now is that I need more "Y="s to complete my picture, since it consists alot of semi circle equations(my picture has alot of circles).....

If not (sigh), can anybody else think of some intricate but reasonable pictures that I can make? At the moment, I'm making headphones :)

2. Sep 20, 2008

### HallsofIvy

Staff Emeritus
You have three choices.

1) Graph y= x2 and turn your calculator on its side.

2) Graph the "inverse" function $y= \sqrt{x}$. Because f(x)= x2 does not have a true inverse, that does not give you the entire parabola- there is no function that is the "inverse" of f(x)=x2. You will, as you say, have to use two functions, $y= \sqrt{x}$ and $y= -\sqrt{x}$

3) Use the "parametric functions" graphing mode if your calculator has one. Let y= t, x= t^2.

Since you don't say what kind of calculator you have, I have no idea whether it is limited to 10 graphs or not.