Problem with a program concerning composite trapezoid rule

In this program I'm using the composite trapezoid rule on integral dx/(1+x^2) from 1 to 0. I've used the same program with different functions and haven't had issues till I tried it with this function. It says I have an error with line y=f(x); Here is code:

f = @(x) 1/(1+x^2);
a=0;
b=1;
n=100;

format long
h = (b-a)/n;
S = f(a);
i=1:1:n-1;
x=a+h*i;
y=f(x);
S=S+2*sum(y);
S=S+f(b);
F=h*S/2

Answer 1

[sixwwwwww]

Dear Drake, re-write first line as:

f = @(x) 1./(1+x.^2);

then it should work. Good luck!