(*						      *)
(* Numerical Mathematics and Computing, Fifth Edition *)
(* Ward Cheney & David Kincaid		              *)
(* Brooks/Cole Publ. Co.			      *)
(* (c) 2003                                           *)
(* No warranties implied or expressed.	              *)
(* File: wave					      *)
(* PDE: solve wave equation * plot		      *)

soln=NDSolve[{D[u[x,t],t,t] == D[u[x,t],x,x], u[x,0]== Sin[Pi*x],
        Derivative[0,1][u][x,0]==0, u[0,t]==0, u[1,t]==0}, u, {x,0,1}, {t,0,1}]
Plot3D[Evaluate[u[x,t] /. First[soln]], {x,0,1}, {t,0,1}, PlotPoints-> 30]
ContourPlot[Evaluate[u[x,t] /. First[soln]], {x,0,1},{t,0,1},
PlotPoints->30, Contours->30, ContourLines->False, ColorFunction->Hue, 
PlotRange->All]