Originally Posted by

**olski1** Hey guys having trouble getting the same answer in the text book.

Question: Consider solving wave equation (c=1) for string length Pi with fixed endpoints u(0,t)=0 and u(pi,t)=0 and initial velocity = 0 and displacement = 0.02sinx.

So after doing the usual steps i arrived at $\displaystyle u_n(x,t) = \sum_{n = 1}^\infty (Ancos(nt) + Bnsin(nt))*sin(nx)$

Using the initial conditions and fourier coefficient formula's i have Bn=0

and $\displaystyle An=\frac{2}{\pi } \int 0.02sin(x)*sin(nx) dx$