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  1.  #include <iostream>
  2.     #include <cmath>
  3.     using namespace std;
  4.  
  5.     int main() {
  6.     	double E, a = 2, sum = 2;
  7.     	cin >> E;
  8.     	for(int i=1; abs(a*=2.0/(i+1))>=E;i++){
  9.     		sum+=a;
  10.     	}
  11.     	cout << sum;
  12.     	return 0;
  13.     }
Success #stdin #stdout 0s 3416KB
comments (?)
stdin 
0.00001
stdout 
6.38905
https://ideone.com/WWsfnu
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
secret

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