#### Topic: Rotating an Oval

I'm currently doing a project where we have to make a picture with various graphs.
I need help rotating an oval about 45 degrees to fit my picture.

http://mario.neoseeker.com/w/i/mario/e/ … _Mario.jpg

This is the picture. The oval i'm trying to make can be seen right above the character's hat.

Is there anyway I can rotate an oval?

Let's say the (standard) function was: -sqrt(.2 - ((x-1.6)^2)/(4^2)(1^2)) -2.3

How do I go abouts this?

#### Re: Rotating an Oval

This is called transformation. I have attached a file that shows it. The file contains your oval as the custom function g(x) and angle=45 is created as a constant.

The rotated functions is then plotted as the parametric function:

``````x(t) = t*cos(angle) - g(t)*sin(angle)
x(t) = t*sin(angle) + g(t)*cos(angle)``````

You can try to see what happens when you change the angle.

#### Re: Rotating an Oval

Wow! This is really very nice I am glad that I learned this. Thank you very much.

#### Re: Rotating an Oval

Thanks Ivan.

I'm having trouble converting the "sqrt(.2 - ((x-1.6)^2)/(4^2)(1^2)) -2.3" to the x(t) = t*cos(angle) - g(t)*sin(angle)
format. Could you help me out? :S

#### Re: Rotating an Oval

Did you look at the file Transformation.grf? It shows exactly how to do it. You can see the function in the Functions|Custom functions dialog where you can change both the function and the angle.

#### Re: Rotating an Oval

I did not know about Custom Functions XD, but yes I was able to get it to work.

Thank you very much Ivan