please help

QUESTION 1 Assume that for a E R, f is 21-periodic, g (x) = f (-x) and h (x) = f (x - a) . Denote by A, and By the Fourier coefficients of f. For all n 2 1, show that (Explain all the steps!): a) An = Bj, A; = As, and B. = - B9. (10 Marks) b) Ap = Ah, Ah = Af cos ann - B. sin " and Ba = Afsin ann + Bf cos in (15 Marks)