Question

L {e^-3t cos2t} is equal to

Answer 1

Answer:

This transform goes like as follow

given

f(t)=t^2 e^(-2t)cos(3t)

cos(3t) ———— —————— s/(s^2 + 9)

t*cos(3t) —————————— (s^2 -9)/(s^2 + 9)^2

t*t*cos(3t) —————————- 2s(27 - s^2)/(s^2 + 9)^3 ———equation(3)

e^(-2t)*t*t*cos(3t) —————— 2(s+2)(27 - (s+2)^2)/{(s+2)^2 + 9}^3 —equation(4)

if there is e^-2t then answer is above mentioned equation (4)

if there is e^-2x then answer is above mentioned equation (3) multiply by e^(-2x)