f = @(x) (1/x);
ll = 1;
ul = 7;

n = 10^4;
h = (ul - ll) / n;

result = f(ul) + f(ll);

for i = (ll + h):2*h:(ul - h)
    result = result + 4*f(i);
end

for i = (ll + 2*h):2*h:(ul - h)
    result = result + 2*f(i);
end

result = result * h / 3;
disp("I = " + result);