How to evaluate these convolutions:
a) y(t) = (u(t) - u(t-2)) * u(t)
b) z(t) = cos(pi*t)(u(t+1) - u(t-1)) * u(t)
c) n(t) = (e^at)u(t) * (u(t+2) - u(t))
where * represents convolution symbol
( integral from T= minus infinity to T=infinity u(T) . u(t-T)dT ) - ( integral from T= minus infinity to T=infinity u(T) . u(t-2-T)dT )
I know that when we integrate with u(t), the integral starts from zero to infinity...Then, I couldn't solve the rest...