Say we have random variables A and B who are described by a joint PDF which is uniform in the unit circle, that is, the set of points that satisfy a^2 + b^2 <= 1. Is it correct that the joint PDF takes the value of 1/pi on the unit circle? Now say we have a function of A and B, a random variable C defined as the square root of (A^2 + B^2). This is the distance of the outcome (A, B) from the origin. Correct? What is the PDF of C in the interval between 0 and 1