Originally Posted by
ldacoll Change the equation to rectangular cordinates
r=2
To convert a function from polar to rectangular or vice versa, use the following conversions:
$\displaystyle r=\sqrt{x^2+y^2}$
$\displaystyle \theta=tan^{-1}\frac{y}{x}$
$\displaystyle x=rcos\theta$
$\displaystyle y=rsin\theta$
$\displaystyle tan\theta=\frac{y}{x}$
Converting $\displaystyle r=2$ to rectangular, we get:
$\displaystyle \sqrt{x^2+y^2}=2\rightarrow x^2+y^2=4$.
You should recognize this as being a circle centered at the origin with a radius of 2.