# convert to polar

• May 7th 2008, 03:44 PM
ldacoll
convert to polar
Change the equation to rectangular cordinates
r=2
• May 7th 2008, 04:01 PM
icemanfan
Quote:

Originally Posted by ldacoll
Change the equation to rectangular cordinates
r=2

You should recognize that this is the equation for a circle with its center at the origin. The form of this equation is $\displaystyle x^2 + y^2 = r^2$. So then, what is the equation for $\displaystyle r = 2$?
• May 7th 2008, 09:24 PM
Chris L T521
Quote:

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.