Hi there,

I have a trigonometrical-series type of solution as follows:

$\displaystyle C=C_{0}-\frac{4C_{0}}{\pi}\sum\frac{(-1)^n}{2n+1}\exp(\frac{-D(2n+1)^2\pi^2t}{4l^2}\cos(\frac{(2n+1)\pi\times(x )}{2l})$

I am having trouble calculating the sum part of the expression. Let's assume

$\displaystyle \frac{Dt}{l^2}=1$ and x = 0 and divide through by $\displaystyle C_{0}$, then I get the sum part to be:

$\displaystyle \sum\frac{(-1)^n}{2n+1}\exp(\frac{-(2n+1)^2\pi^2}{4})\times1$

The reference I am using gives the overall answer to be:

$\displaystyle \frac{C}{C_{0}}=1 - 0.1080 = 0.8920$

but I am gettingmuchsmaller answers. Could anyone suggest what I might be doing wrong?

Any help would be much appreciated