1. The problem statement, all variables and given/known data Solve the following differential equation, by using the substitution u = y'.: (y + 1) y'' = (y')^2 2. Relevant equations I'm assuming: Chain Rule 3. The attempt at a solution My problem is, simply, that I don't get how to go from u = y' to y'' = u du/dy, and I would appreciate it if someone could show me how! Other than that, I should be fine.