Find the Polar Coordinates...

(-5,12) are the rectangular coordinates of a point. Find two pairs of polar coordinates (r,A) for each point, on with r>0 and one with r<0. Express A in radians. Please help! please explain process and answer, im working on a similar problem with a tutor and she is not very much help.

Re: Find the Polar Coordinates...

$\displaystyle r= \sqrt{x^2+ y^2}$ and $\displaystyle \theta= tan^{-1}\left(\frac{y}{x}\right)$. "Negative r" would be unusual notation but you would just add or subtract $\displaystyle \pi$ from the angle, A.