Wow I am so very bad at differential equations.. :( The problem Here is the exact problem I'm given: http://img229.imageshack.us/img229/9025/10640260bs5.jpg [Broken] attempt at a solution I'm guessing that I need to differentiate y(x) that I am given and substitute that into the left hand side and then put the y function [sinx + 1/u(x)] as y in the right hand side (y^2). Then re-arrange for u(x) and differentiate to get du/dx and hopefully it will be the third given equation. After that I think I just have to solve that ODE and get it back in terms of y. Assuming that is what I have to do, sadly I cannot even get that far.. differentiating y(x) = sinx + 1/u(x) must this be done implicitly? I get confused as u(x) is a function and not a variable. I can see that the third equation must be solved linearly such that dy/dx + utan(x) = -1/2 sec(x) And I (think) that I solved the integrating factor to be 1/cos(x). But I am so bad at differential equations and the sources on the internet seem to be so confusing that I'm quite stuck from here but this is what I have: (1/cos(x))*du/dx + u*(1/cos(x))*tan(x) = -(1/2)*(1/cos(x))*sec(x)=d/dx(u/cos(x)) <- multiplying by integrating factor and copying form of examples from the net u/cos(x) = integral of -(1/2)*(1/cos(x))*sec(x) and I know I'm way off here so I think I might aswell just stop... Also it would be great if someone could point me in the direction of a site that shows how to type all those math symbols such as the integral sign. Thanks in advance. A lot.