1. The problem statement, all variables and given/known data Establish an equation in polar coordinates for the curve x^2+y^2=4y-2x 2. Relevant equations n/a 3. The attempt at a solution I know that x^2+y^2=r^2 so I used substitution, and now have r^2=4y-2x. Now this next part, I'm really not sure if I'm allowed to do this... i know that x=rcos@ (let @=theta) and y=rsin@. So i simply substituted to get r^2=4rsin@-2cos@. Is that allowed? Also, i feel like my answer should just look like r=..... So should I take the sqaure root of both sides? Thank you, very appreciated.