For the benefit of others who will look at this thread, the questions are:

1. Solve:

(a) .

(b) .

2. Solve (express the answer as a convolution):

.

As a matter of courtesy you should have done what I've done above, especially given the sort of reply you're hoping to get.

There is a lot ofroutinehack work that can be done simply by applying the various formulae. So what I want to know is what haveyoudone so far? Where exactly are you stuck?

Please show all the work you've been able to do.

You will also find in these forums (use the search option) several detailed solutions to similar questions.