Prove mathematically that the signals given are periodic. For each signal, find the fundam...

Prove mathematically that the signals given are periodic. For each signal, find the fundamental period T0 and the fundamental frequency ω0.

(a) x(t) = 7 sin3t

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(b) x(t) = sin(8t + 30°)

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(c) x(t) = ej2t

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(d) x(t) = cos (2t) + sin (5t)

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(e)

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(f) x(t) = e–j15t – ej20t