#include <iostream>
#include <cmath>

using namespace std;

double arcsin(double x, double eps = 1e-7)
{

    double term = x, sum = term;
    x *= x;
    for(int k = 1; abs(term) > eps; k+=2)
        sum += (term *= x*k/(k+1))/(k+2);
    return sum;
}

int main()
{
    for(double x = 0; x < 0.8; x += 0.1)
        cout << asin(x) << "    " << arcsin(x) << endl;
}