#include <iostream>
#include <cmath>
using namespace std;
double arctg(double x, double eps = 1e-10, int n = 0)
{
double t = pow(x,2*n+1)/(2*n+1)*(1-2*(n%2));
if (abs(t) > eps) return arctg(x,eps,n+1) + t;
else return t;
}
int main(int argc, char * argv[])
{
for(double x = 0; x < 0.7; x += 0.1)
cout << x << " " << atan(x) << " " << arctg(x) << endl;
}
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