Problem $6,10$pt

Problem $3\mathrm{.}3$ on the reference book. Find the Laplace transform of the following time

functions. Look up the table and apply the properties of Laplace transformation.

$($a$)f(t)=3cos6t$

$($b$)f(t)=sin2t+2cos2t+e^{-t}sin2t$

$($c$)f(t)=t^2+e^{-2t}sin3t$