Question: Simpson Rule not working in Maple?

I can't get Simpson's Rule to work properly in Maple for f(x)=cos(e^-x)

According to Wolfram Alpha, I should be getting something like -0.5. Clearly that's not what I'm getting. Please help?

> f := proc (x) options operator, arrow; cos(6*exp(-x)) end proc;
x -> cos(6 exp(-x))

S := evalf(int(f(x), x = 0 .. 1));
                         -0.4411788573
S1 := evalf((1/6)*(1+0)*(f(0)+4*f(1)+f(2)));
                         -0.1215440391
S2 := evalf((1/12)*(1+0)*(f(0)+4*f(1)+2*f(2)+4*f(3)+f(4)));
                          0.3979663797
S-S1;
                         -0.3196348182
100*(S-S1)/S;
                          72.45016685
S-S2;
                         -0.8391452370
100*(S-S2)/S;
                          190.2052247