Explain the answer please with the steps

t , 0 2 Answer: f() = [u(t)- u(t-2)]t+u(t-2)eat sin[3(t- 2)] - u(t)t +u(t-2)[-t + e2t sin[3(t-2)]] = - u(t)t + u(t - 2) fete2(t ?) sin[3(t - 2)] - (t - 2) - 2}