> restart;

> u50 := (x,y) -> Sum(((4/(n*Pi) - 2/(n*Pi)*(-1)^n)* cos( 2*n*y) + (1-(-1)^n)/(n*n*Pi)* sin(2*n*y)) *sin(n/2*x), n=1..50);

> plot3d( u50(x,y), x=0..2*Pi, y=0..6, labels =[`x`, `time`, `u(x,t)`], axes=FRAMED, style=patch);

> v1 := (x,y) -> Sum(((4/(n*Pi) - 2/(n*Pi)*(-1)^n)* cos( 2*n*y) + (1-(-1)^n)/(n*n*Pi)* sin(2*n*y)) *sin(n/2*x), n=1..1);

> plot3d( v1(x,y), x=0..2*Pi, y=0..6, labels =[`x`, `time`, `u(x,t)`], axes=FRAMED, style=patch);

> v2 := (x,y) -> Sum(((4/(n*Pi) - 2/(n*Pi)*(-1)^n)* cos( 2*n*y) + (1-(-1)^n)/(n*n*Pi)* sin(2*n*y)) *sin(n/2*x), n=2..2);

> plot3d( v2(x,y), x=0..2*Pi, y=0..6, labels =[`x`, `time`, `u(x,t)`], axes=FRAMED, style=patch);

> v6 := (x,y) -> Sum(((4/(n*Pi) - 2/(n*Pi)*(-1)^n)* cos( 2*n*y) + (1-(-1)^n)/(n*n*Pi)* sin(2*n*y)) *sin(n/2*x), n=6..6);

> plot3d( v6(x,y), x=0..2*Pi, y=0..6, labels =[`x`, `time`, `u(x,t)`], axes=FRAMED, style=patch);

>