[SOLVED] converting polar equations to rectangular equations

**satis** · April 7th 2010, 02:00 PM

I'm pretty stuck here.. any assistance would be helpful

given $r=3cos\Theta$ , convert to rectangular form

I know that $r^2 = x^2 + y^2$ , so I could square both sides

$r^2 = (3cos\Theta)^2$
$x^2 +y^2 = (3cos\Theta)^2$

But at that point I'm stuck. I have the answer from the back of the book, but can't work out how to complete the conversion.

**skeeter** · April 7th 2010, 02:21 PM

Originally Posted by satis

I'm pretty stuck here.. any assistance would be helpful

given $r=3cos\Theta$ , convert to rectangular form

I know that $r^2 = x^2 + y^2$ , so I could square both sides

$r^2 = (3cos\Theta)^2$
$x^2 +y^2 = (3cos\Theta)^2$

But at that point I'm stuck. I have the answer from the back of the book, but can't work out how to complete the conversion.