(b) Consider the system described as dy(t) dt +ay(t) = u(t). Obtain the step responses of the system for different values of a (i.e., a < 0, a = 0, and a > 0). Let a = 1 and u(t) = sin(t), t 0. Also, let y(0) = 1. Obtain the response of the system and analyze its behavior when t approaches infinity.