I encounter an exercise where $f(t) = \frac{2}{1+t^2}$, and asked to find the convolution of $(f\*f)(t)$. I'm also given the following $(f\*g)(t) = \int\_0^t f(u)g(t-u)du$, but not I'm not sure if it's relevant. I tried looking for some example with full solutions but haven't found any, I'd very much like to know the basic steps on solving this problem so I know how to tackle this kind of problem in the future! Thanks ahead.