1. The problem statement, all variables and given/known data hello, i am stucked at an article from sciencedirect . somewhere it gives me the following equation and then it tells that this equation must have 4 complex roots! the variable is lambda and we want to find 4 lambda complex roots 2. Relevant equations λ^4=0 3. The attempt at a solution i am amazed how we can get 4 complex roots from this equation as it seems to have roots equal to zero ! Any help would be greatly appreciated!