Question

Find the Laplace transform of the function f (t) = tsin2t.

(a) 4s/(s^2+4)^2

(b) -4s/(s^2+4)^2

(c) -4s/(s^2-4)^2

(d) 4s/(s^2-4)^2

Answer 1

Right option is (a) 4s/(s^2+4)^2

Explanation: The Laplace transform of the function of sin2t is L(sin2t)=2/(s^2+4). So the Laplace transform of the function f (t) = tsin2t is L(tsin2t) = -d/ds [2/(s^2+4)] = 4s/(s^2+4)^2.