The Fourier series expansion of a real periodic signal with

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The Fourier series expansion of a real periodic signal with fundamental frequency f 0 is given by
_{n = ∞}
g_P(t) = C_n.e^j2πnf₀t
^{n = – ∞}

It is given that C₃ = 3 + j5 then C_{– 3} is—

1. 5 + j3
2. – 3 – j5
3. – 5 + j3
4. 3 – j5

Correct Option: D

If function is real (as given), then
x(t) = x*(t)
or x[t] = a_k = a*_{– k}
So, c_{– 3} = c₃* = 3 – j5
Hence, alternative (D) is the correct choice.