Plz explain workings az wel az answer

An Amplitude Modulated (AM) radio signal is given by s(t) = sin(ct) cos(at) Differentiate this function with respect to t. By considering the Maclaurin series for sin(wt) and cos(at), find a Maclaurin series for the signal function s(t) up to the first three non-zero terms. If the complex number z is defined as z = (w + ik)t, write down the real and imaginary parts of ell. By writing real and imaginary parts of e" and e" show that e * + ell = 2 cosx