# Horrible expression involving logs and inverse tan functions

1. Jul 9, 2011

### coverband

1. The problem statement, all variables and given/known data

$$\frac{d^2y}{dx^2} + (y^4-1)\frac{dy}{dx} = 0$$

2. Relevant equations

$$\frac{dy}{dx} + (y^4-1) = 0$$

3. The attempt at a solution

$$\frac{dy}{dx} = (1- y^4)$$
$$\frac{dy}{1- y^4} = dx$$

Then I get a horrible expression involving logs and inverse tan functions on the LHS and x + A on RHS ???

sorry heading should be ODE not PDE

Last edited by a moderator: Feb 4, 2013
2. Jul 9, 2011

### Klockan3

Re: Pde

You have the wrong expression after the integration, try taking the derivative of that with respect to x to see if you get the same expression as you started with. HINT: You forgot the x to y dependence.