#include <bits/stdc++.h>   using namespace std;   int main() {     long long n;     double r, v, si, fi;     cin >> n >> r >> v;     for (int i = 0; i < n; i++) {       cin >> si >> fi;       double dist = fi - si;       double cir = 2 * 3.14159265358979323846 * r;       double rev = dist / cir;       rev = floor(rev);       double time = rev * (cir / v);       dist -= time * v;       double left = 0;       double right = cir / v;       double x;       while (right - left > 1e-12) {         double mid = (left + right) / 2;         double temp =             2 * r * sin((mid * 3.14159265358979323846) / (cir / v)) + mid * v;         if (temp >= dist) {           right = mid;         } else           left = mid;       }       time += left;       printf( %.12f n , time);     }     return 0;   }   