Show that

part a)

sin(x+iy) = sin x cosh y+ i cos x sinh y

using complex exponentials

This is what i got so far

LHS

sin(x+iy)

RHS

sin x cosh y + i cos x sinh y

when i combine(cross multiply) both the RHS equation i get

Which is equal to

LHS = RHS

part b)

If z = x+iy with x and y real and if sin(z) = 2, deduce that cos x = 0

how do I go upon that?