Hi everyone
This question is from my Signals and Systems class, its an EE course so I'm not sure if this question is appropriate for this "Applied Math" section but maybe someone here can answer me with a concise answer.
Now I've done a bunch of convolution problems before but I always seem to have trouble with the u(t) term, I understand its related to the limits of integration but I don't understand how to get rid of it or multiply it out with other u(t) or u(t tau) terms. There's so much I'd like to say here but I know the human attention span is limited so if someone could try to explain this to me, preferably solve it out in detail (please don't skip any steps). I've also attached my work (#58)to this post which has the equation and a worked out similar problem (#48), this similar problem deals with cos(x) and just 1 u(t) term so I solved it relatively quickly.
Any help or assistance will be much appreciated.

iqbalmmz