# Fourier Coefficient

1. Jul 24, 2010

### josftx

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

Hello, i'm have to resolve a PDE. The result of that analysis and resolution is that fourier series, and i have to find the $$B_n$$ coefficient. because $$A_n$$ i found it.

2. Relevant equations

$$21={\displaystyle \sum_{n=0}^{\infty}[2n\pi B_{n}-A_{n}]sin(\dfrac{n\pi x}{3})}$$

with $$1x\in[0,3]$$

3. The attempt at a solution

$$2A_{n}=\dfrac{4}{3}\int_{0}^{3}sin(\dfrac{n\pi x}{3})$$
$$2B_{n}=?$$

Last edited: Jul 24, 2010