function mnhf_trapz_example(N,subplot_index)
%MNHF_TRAPZ_EXAMPLE estimates the integral of cos(x) from x=0 to x=10 
% using the built-in function trapz. The exact solution is sin(10).
%
% N - Number of grid points
% subplot_index - subplot in which graphical output is shown
%
% Usage  mnhf_trapz_example(11,1);   mnhf_trapz_example(101,2);
%        mnhf_trapz_example(1001,3); mnhf_trapz_example(10001,4);

x = linspace(0.0,10.0,N);
y = cos(x);
subplot(2,2,subplot_index); box on; hold on
plot(x,y,'ko','markersize',4); plot(x,y,'k','linewidth',1)
h = x(2)-x(1);
text(2,0.7,sprintf('h=%4.3f',x(2)-x(1)))
title(['error = ' num2str(abs(sin(10)-h*trapz(y)))])