BC:2.3 Express the following sampled signals usinga sum of weighted impulses (delta functions). If theweights are complex valued (not purely real), thenexpress the weights in polar form with the angle indegrees. (You can use the summation symbol: and specify limits of the summation.)a.)fa[n] = 25 cos(0.25n + 45o) for |n| 40 otherwiseb.)fb[n] = 25 cos(0.25n + 45o) for 3 n 50 otherwisec.)fc[n] = ( jej0.5n1for n 00 otherwised.)fd[n] = ( 22 + 2j2n1for n 50 otherwisee.)fe[n] = ( 22+j21nfor n 40 otherwise