Homework Help: Ellipse Compression and Expansion

1. Apr 22, 2005

cocoavi

An ellipse is defined by the equation $$\frac {x^2}{144} + \frac {y^2}{36} = 1$$. Determine the equation of the ellipse formed when the original ellipse has undergone a horizontal compression by a factor of 1/2 and a vertical expansion by a factor of 3.

I'm not quite sure how to work out the equation.. could someone give me some hints?

2. Apr 22, 2005

Staff: Mentor

You need to recognize the standard form for the equation of an ellipse:
$$\frac {x^2}{a^2} + \frac {y^2}{b^2} = 1$$

That's the equation for an ellipse centered at the origin. The length of the horizontal axis is 2a; the vertical axis is 2b.