A continuous-time periodic signal x(t) is real valued and has a fundamental period T = 8. The nonzero Fourier series coefficients for x(t) are specified as a_1 = a*_-1 = j, a_5 = a_-5 = 2.
Express x(t) in the form
x(t) = sigma^infinity_k=0 A_k cos(W_k t + phi_k).

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