laplace of t2e-t cos at

Question

find laplace transform of t² e^-t cos at

Answer 1

Lap;ace transform of the function f(t) is defind as L(f. s)=∫₀^∞f(t)e^-stdt. 

L(f, s)=∫₀^∞ t²e^-t cos(at)e^-stdt=∫₀^∞ t²e^-t(1+s) cos(at)dt

You need to evaluate this integral.