function integral = traptd2(f,a,b,n)
% Approximates the definite integral of funct from a to b
% using the n-point trapezoidal rule
% T. DeLillo, Math 451, fall 2001
x=linspace(a,b,n);
h=(b-a)/(n-1);
fval = feval(f,x);
integral=(.5*fval(1)+sum(fval(2:n-1))+.5*fval(n))*h;