double NewtonCotes(double a,double b, int n)
{
    double Bk = 2.0/45;
    double h=(b-a)/n;
    double res=0;
    vector <double> coef(n+1,0);
    coef[0] = 7;
    coef[1] = 32;
    coef[2] = 12;
    coef[3] = 32;
    coef[4] = 7;
    for(int i=0;i<=n;++i)
    {
        res+=(func(a+i*h))*Bk*coef[i]*h;
    }
    return res;

}