1. ## Auxiliary Circle

What is auxiliary circle. please tell me what is the equation of auxiliary circle corresponds to ellipse
$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$

2. ## Re: Auxiliary Circle

Maybe this can be useful:
Auxiliary Circle -- from Wolfram MathWorld

3. ## Re: Auxiliary Circle

Originally Posted by waqarhaider
What is auxiliary circle. please tell me what is the equation of auxiliary circle corresponds to ellipse
$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$
If you let $M=\max(a^2,b^2)$ then $\frac{x^2}{M}+\frac{y^2}{M}=1$ works nicely.

4. ## Re: Auxiliary Circle

thanks Siron and Plato from your help the equation of auxiliary circle will be
$x^2+y^2=a^2$ for a>b thank you again