Use the Fourier transform definition to compute the Fourier transform of the followin a)
f_(a)(t)=cos(\pi t)*[u(t+3)-u(t-3)]
b)
f_(b)(t)=t[u(t-3)-u(t-4)]
c)
f_(c)(t)=5\delta (t-5)
d)
f_(d)(t)=e^((t)/(5))u(-t)