double RowFunction(double x) {
    double sum = 0;
    int i = 1;

    while (fabs(sum - log(x)) > 0.1) {
        sum += pow(x - 1, i) / (i*pow(x, i));
        i++;
    }

    return sum;
}

int RecursionFunction(int i, int n, double xs[], double array[]) {
    if (i < n)
        array[i] = log(xs[i]);
    if (i + 1 < n)
        RecursionFunction(i + 1, n, xs, array);
    return 0;
}

double recurLog(double x, int n)
{
    if (n == 1) return (x-1)/x;
    double n_term = 1;
    for(int i = 0; i < n; ++i)
        n_term *= (x-1)/x;
    n_term /= n;
    return recurLog(x,n-1) + n_term;
}

double serialLog(double x, int n)
{
    x = (x-1)/x;
    double term = x, sum = x;
    for(int i = 2; i <=n; ++i)
        sum += term *= x*(i-1)/i;
    return sum;
}