Task №1

#include <iostream>
#include <cmath>
using namespace std;

double Sh(double x, double eps)
{
    double an = x, sum = an;
    int i = 0;
    while (fabs(an) > eps)
     { an *= -(x*x)/((2*i+1)*(2*i+2));
       sum += an;
       i++;
     }
    return sum;
}

double Sder(double x, double eps)
{
    double an = 1, sum = an;
    int i = 0;
    while (fabs(an) > eps)
     { an *= -(((x*x*(2*i+3)))/((2*i+1)*(2*i+1)*(2*i+2)));
       sum += an;
       i++;
     }
    return sum;
}


int main()
{
    double x, eps;
    for (x=0; x<=1.8; x+=0.1)
    {
        cout << "\nSh(" << x << ") = " << Sh(x, eps);
        cout<<"\nSder(" << x << ") = " << Sder(x, eps);
        cout<<"\nSright(" << x << ") = " << (Sh(x+0.1,eps)-Sh(x, eps))/0.1;
        cout<<"\nSleft(" << x << ") = " << (Sh(x, eps)-Sh(x-0.1,eps))/0.1;
        cout<<"\nSaver(" << x << ") = " << (Sh(x+0.1, eps)-Sh(x-0.1,eps))/0.2;
        cout << "\nxcos(" << x << ") = "<< x*cos(x);
        cout << "\n" << endl;
    }
    return 0;
}