function I = TrapComp(f,a,b,n)
%
% TrapComp estimates the value of the integral of f(x) from a to b
% by using the composite trapezoidal rule applied to n equal-length 
% subintervals.
%
%   I = TrapComp(f,a,b,n) where
%
%     f is an inline function representing the integrand,
%     a and b are the limits of integration,
%     n is the number of equal-length subintervals in [a,b],
%
%     I is the integral estimate.
%
h = (b-a)/n; I = 0;
x = a:h:b;
for i = 2:n,
    I = I + 2*f(x(i));
end
I = I + f(a) + f(b);
I = I*h/2;