1. The problem statement, all variables and given/known data Sorry for the mis-spelled title - it's "series". Please take a look at http://www-solar.mcs.st-and.ac.uk/~alan/MT2003/PDE/node21.html In step 2.60, when he wants to find the coefficient B_n, the argument in the sine-function does not contain a "2". In my book, the argument in the sine function is 2*pi*n*x/L, where L is the period. Why is this "2" not in the example?