22.Тейлор

#include "stdafx.h"
#include <cstdlib>
#include <iostream>
#include <math.h>

using namespace std;

double ln(double x);

int main() {
    double x=0.5;
    double sum = ln(x);
    cout << sum << " " << log(1+x) << endl;
    system("pause");
    return 0;
}
double ln(double x) {
    double n = x;
    double sum = 0;
    int i = 2;
    do
    {
        sum += n;
        n = pow(-1.0,i+1) * pow(x, i) / i;
        i++;
    } while (fabs(n) > 0.00000000001);
    return sum;
}