Question

Giúp e

Answer 1

Câu 7: 

#include <bits/stdc++.h>

using namespace std;

long long n,i;

double s;

int main()

{

cin>>n;

s=0;

for (i=1; i<=n; i++)

if (i%2==0) s=s+1/(i*1.0);

cout<<fixed<<setprecision(2)<<s;

return 0;

}