function quad=gauss(a,b)
quad=((b-a)/2)*(f((a+b)*0.5+0.5*(b-a)*0.9061798459)*0.2369268851+f((a+b)*0.5+0.5*(b-a)*(-0.9061798459))*0.2369268851+f((a+b)*0.5+0.5*(b-a)*0.5384693101)*0.4786286705+f((a+b)*0.5+0.5*(b-a)*(-0.5384693101))*0.4786286705+f((a+b)*0.5+0.5*(b-a)*0.0)*0.56888888888);
disp('****** this is the integral using G5 *************')
quad