function Oct9()

% If I = integral from -1 to 1 of f(x) and 
%    QG2 = .5*f(-1/sqrt(3)) + .5*f(1/sqrt(3))
% then 
%         | I - QG2 | <= M4/135         M4 bounds 4th derivative of f
%
% If I is the integral from c to d of f(x) and
%
%    QG2 = .5*ftilde(-1/sqrt(3)) + .5*ftilde(1/sqrt(3))
%
% where ftilde(x) = f(-1+2(x-c)/(d-c)) then
%
%        |I - QG2 | <= ????
%
% Composite rule based on n equal subintervals of [a,b]

IQG = 0;
h = (b-a)/n;
for k=1:n
    c = a + (k-1)h
    d = c+h;
    % Apply QG2 to integral from c to d...
    Ik =
    IQG = IQG + Ik;
end

