function comp_trapez
n=90; % the number of nodes. 
a=0; b=10; % the interval [a,b]
h=(b-a)/n; % the step size
%%%%% THE Composite Trapezoidal RULE %%%%%
%%%%% TO CALCULATE \int_{a}^{b} f(x)dx
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
S=f(a);
for i=1:1:n-1
  S=S+2*f(a+i*h);
end;
S=S+f(b);
S=(h/2)*S;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% compare to the exact integral 
S+(cos(b)-cos(a))
  



function y=f(x);
y=sin(x);