answer the problem below

Question 3 Problem 3: Determine the Fourier series coefficients for a (t) = cos(nt) = _ (- 1)* (u ( t + 2 - ) - 2(t - 2 - k)) Ock = 1, k = 11; 0 otherwise O sin Ck k even; 0 otherwise k O sin "(1-2k) Ck + sin ( (1+2k)) 7(1-2k) #(1+2k) k = 0, +1, +2, .. . None of the above