t=0.;
x=0.;
Plot[{Sin[2Pi 440 x/340-2Pi 440t],1.5Sin[2Pi 440 x/340-2Pi 440t+Pi/2],Sin[2Pi 440 x/340-2Pi 440t]+1.5Sin[2Pi 440 x/340-2Pi 440t+Pi/2]},{t,0,10^-2},PlotStyle->{RGBColor[1,0,0],RGBColor[0,0,1],RGBColor[0,1,0]}]

x=0.;
Plot[{Sin[2*Pi*440*x/340-2*Pi*440t],Sin[2*Pi*1320*x/340-2*Pi*1320t],Sin[2*Pi*440*x/340-2*Pi*440t]+Sin[2*Pi*1320*x/340-2*Pi*1320t]},{t,0,10^-2},PlotStyle->{RGBColor[1,0,0],RGBColor[0,0,1],RGBColor[0,1,0]}]

t=0.;
Plot[{Sin[2*Pi*440*x/340-2*Pi*440t],Sin[2*Pi*1320*x/340-2*Pi*1320t],Sin[2*Pi*440*x/340-2*Pi*440t]+Sin[2*Pi*1320*x/340-2*Pi*1320t]},{x,0,5},PlotStyle->{RGBColor[1,0,0],RGBColor[0,0,1],RGBColor[0,1,0]}]

t=0.;
Plot[{Sin[2*Pi*880*x/340-2*Pi*880t],Sin[2*Pi*1320*x/340-2*Pi*1320t],Sin[2*Pi*880*x/340-2*Pi*880t]+Sin[2*Pi*1320*x/340-2*Pi*1320t]},{x,0,5},PlotStyle->{RGBColor[1,0,0],RGBColor[0,0,1],RGBColor[0,1,0]}]

L=0.5;
v=275.;
t=0.;
Animate[Plot[Sum[(-1)^((n+1)/2 +1)8/(2Pi^2 n^2)(Sin[n Pi/L(x-v t)]+Sin[n Pi/L(x+v t)]),{n,1,51,2}],{x,0,.5},PlotRange->{-1.0,1.0},PlotStyle->RGBColor[1,0,0]],{t,0.,.01,.0001},DefaultDuration->10]

L=0.5;
v=275.;
t=0.;Plot[Sum[(-1)^((n+1)/2 +1)8/(2Pi^2 n^2)(Sin[n Pi/L(x-v t)]+Sin[n Pi/L(x+v t)]),{n,1,51,2}],{x,0,.5},PlotRange->{-1.0,1.0},PlotStyle->RGBColor[1,0,0]]