1. The problem statement, all variables and given/known data Find the unit impulse response for the operator D^4 + I, using the Laplace transform. 2. Relevant equations 3. The attempt at a solution w^(4) + w = δ(t) s^4W + W = 1 W = 1 / (s^4 +1) Now, I need to find the inverse laplace transform of W. But I don't know how to simplify W. Should I use partial fractions? If so, how do I factor the denominator? (Note: In the first line "^(4)" refers to the fourth derivative with respect to t.