function f = Int1(a, b)
x = a;
f =0;
f = f - 0.2*x + 25*x^2/2 -200*x^3/3+ 675*x^4/4-900*x^5/5+ 400*x^6/6;
x = b;
f = f + 0.2*x + 25*x^2/2 -200*x^3/3+ 675*x^4/4-900*x^5/5+ 400*x^6/6;
end