The Problem You are given: http://img530.imageshack.us/img530/4468/88346476ca9.jpg [Broken] Where http://img408.imageshack.us/img408/209/53113174nt5.jpg [Broken] is constant (taken as B). a) Differentiate both sides to produce a second order ODE for y(x) b) Show that it can be written as a first order ODE for u=dy/dx http://img229.imageshack.us/img229/5861/81200662fv5.jpg [Broken] c) Find the general solution for part b), you should have two arbitrary constants. 2. Relevant equations The fundamental theorem of calculus: 3. The attempt at a solution a) Using fundamental theorem of calculus, d2y/dx2 = Bf(x) => d2y/dx2 = B(1 + (dy/dx)2)1/2 b) Let u = dy/dx => du/dx = B(1 + (dy/dx)2)1/2 = B(1 + u2)1/2 c) Not a clue.. I have actually got no idea where to start for this. I would solve du/dx first, but wouldn't that just result in what I was given, the equation for part a)? Thanks in advance.