Question

Which of the following impulse responses correspond(s) to stable LTI systems? (a) h1(t) = e-(1-2j)ru(t) (b) h2(t) = e-r cos(2t)u(t)

Answer 1

LTI system is stable if Impulse response is finite.

so the correct answer is "b"

(b) h2(t) = e-r cos(2t)u(t)