Plots for the last example in 11.7 lecture, f(x,y) = sin(pi*x)sin(pi*y). 

>	plot3d(sin(Pi*x)*sin(Pi*y),x=-3..3,y=-3..3,numpoints=10000);

 

>	contourplot(sin(Pi*x)*sin(Pi*y),x=-5..5,y=-5..5,numpoints=10000);

 

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