#include <math.h>
#include <stdio.h>
double const pi = 3.1415926535897932385;
static double f0(double x){
  if (x<0) return f0(-x);
  if (2.*x>pi) return -f0(x-pi);
  return 1;}
static double fs(double x, int n){
  double s = 0;
  while (n--) if(n&1) s += (n&2?-1:1)*cos(n*x)/n;
  return 4./pi*s;}
static void rp(double x){
  printf("%11.6f %11.6f %20.15f\n", x, f0(x), fs(x,10000));}
int main(){
  rp(0); rp(pi/2+0.01); rp(pi/2-0.01); rp(1); rp(-4); rp(7); rp(11.53);
  return 0;}

/*
   0.000000    1.000000    0.999936338023400
   1.580796   -1.000000   -0.994543529084521
   1.560796    1.000000    0.994543529084516
   1.000000    1.000000    1.000112183603661
  -4.000000   -1.000000   -0.999968592091892
   7.000000    1.000000    0.999952084712269
  11.530000    1.000000    1.000114735365318
*/