# Math Help - Rectangular form into Polar Form

1. ## Rectangular form into Polar Form

how do you change the rectangular equation (x+1)^2 + y^2 = 1 into polar form?

2. Originally Posted by jumpman23
how do you change the rectangular equation (x+1)^2 + y^2 = 1 into polar form?
Expand:

$x^2+2x+1+y^2=1\implies x^2+y^2+2x=0$

Convert:

$x^2+y^2+2x=0\implies r^2+2r\cos\theta=0$

Simplify (solve for r):

$r^2+2r\cos\theta=0\implies r^2=-2r\cos\theta\implies r=-2\cos\theta$

Does this make sense?

3. yes it does. thank you so much for your help.