FilledPlot[{h[x],average},{x,a,b}] ![[Graphics:1108.q8gr2.gif]](1108.q8gr2.gif)
FilledPlot[y[x],{x,a,b},Fills->
RGBColor[0.5,0.2,0.3]}] ![[Graphics:1108.q8gr2.gif]](1108.q8gr2.gif)
SurfaceOfRevolution[y[x],{x,a,b},RevolutionAxis->{1,0,1}] ![[Graphics:1108.q8gr2.gif]](1108.q8gr2.gif)
Plot[y[x],{x,-1,14},PlotPoints->1000,AspectRatio->0.5,
Background->RGBColor[1,1,0.9], GridLines->Automatic] ![[Graphics:1108.q8gr2.gif]](1108.q8gr2.gif)