# Math Help - [SOLVED] convert circle of center (1,0) and radius 1 to polar coordinates

1. ## [SOLVED] convert circle of center (1,0) and radius 1 to polar coordinates

I suppose this is really simple, but how does one go from: $(x-1)^2 + y^2 = 1$ to the equivalent polar coordinate equation.

Thanks.

2. Plug'n Chug! It's not magic. It's an algebra problem.

$x = r\cdot\cos(\theta)$

$y = r\cdot\sin(\theta)$

Expand, Simplify, etc.

3. Originally Posted by nunos
I suppose this is really simple, but how does one go from: $(x-1)^2 + y^2 = 1$ to the equivalent polar coordinate equation.

Thanks.

$x=r\cos \theta\,,\,y=r\sin \theta$ , and then $(x-1)^2+y^2=1\Longrightarrow x^2-2x+y^2=0\Longrightarrow r(r-2\cos \theta) = 0$ $\Longrightarrow r = 2\cos \theta$

Tonio