1. The problem statement, all variables and given/known data a) s^2*t''+st*t'=s b) y(dx/dy)^2=x^2+1 c) 17y''''-t^6*y"-4.2y^5=3cost(t) 2. Relevant equations 3. The attempt at a solution For part a I thought about doing a reduction of order but I can't because I have the variable s present. Not sure what my other options are. Part b I solved for dx/dy but now I'm stuck. Can't think clearly Part c I'm not even remotely sure on how to do this. I was thinking integrating factor but I don't know.