1. The problem statement, all variables and given/known data Find the general solution of (D^4 - I)^2(D^2 - 4D + 13I)^2(y) = 0 2. The attempt at a solution My issue with this problem is that I have no clue as to what the I's mean. I have become familiar with D being used notationally with differential equations, but the introduction of the I's is totally foreign to me, and my professor has never even addressed them. Am I supposed to assume the I's are simply a constant, or am I totally missing something here? I can break the problem down to the following, though: [(D^2 + sqrt(I))(D + sqrt(I))(D - sqrt(I))]^2 * [D^2 - 4D +13I]^2 * y = 0 From here, am I supposed to proceed "as usual" with solving the equation... or do the I's have some significance? It seems very possible to solve w/ I's being a constant, but absolutely brutal to actually find the gen. solution for :/ Thank you for any help!