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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. int main() { // for 25
  5. double X;
  6. int N;
  7. cin >> X >> N;
  8.  
  9. double S = 0.0;
  10. double t = X;
  11. S += t;
  12.  
  13. for (int k = 2; k <= N; ++k){
  14. t = -t * X * (double)(k - 1) / k;
  15. }
  16. cout << S << endl;
  17. return 0;
  18. }
Success #stdin #stdout 0.01s 5324KB
stdin
1.5 7
stdout
1.5