Signals and systems Definition and 52 Threads

hey guys - attached is a solution to a signals related question. Given the system - we must calculate the impulse reponse. please click on attachment to see what I am talking about. two things confuse me: 1)the system is evidently non-causal, but here they decide to shift the entire...

I have a question about finding the signal energy of a signal? What exactly are you suppose to do when you are given a certain function like x(t)=rect(t) sin(2*pi*t)?