I have three random variables where $ a $ and $b$ are uniformly distributed between $[-1/2, 1/2]$ and $c = a + b$. Also, $b$ is independent of $a$. How can I find the joint pdf of $a$ and $c$?
So far I've been looking at this formula:
Formula for calculating joint pdf
And I know that $f_a = r_1(x)$, the rectangular function with width 1. How can I calculate $f_{c|a}$?