Find a general solution to: y'' -2y' - 3y = 3te^-t
This is what i did: i found the fundamental set of solution which is a(t) = e^3t and b(t) = e^-t
Then for my guess i used u(t) = Ate^-t and got y(t) = c1e^3t + c2e^-t -te^-t which is wrong according to my book.
