# The 2D wave-equation: d'Alemberts method

1. Oct 17, 2008

### Niles

1. The problem statement, all variables and given/known data
I am given an initial- and boundary value problem for the two dimensional wave function, and I must solve it by d'Alembert's method.

It is all good, but I am given the initial velocity: $g(x)=x(\pi-x)$.

I have to find the odd extension of this on the interval $-\pi$ to $\pi$. I don't like using Fourier series, because I must integrate the odd extension. Is there any way to do this?