1. The problem statement, all variables and given/known data I'm reading a book where they do the following steps which I don't understand: We have a DE: b^2 * y'' = axy put t = b^(-2/3) a ^(1/3) x then somehow get (d^2 y)/dt^2 = ty how? 2. Relevant equations None. 3. The attempt at a solution I tried messing with chain rule but got nowhere.