题解 | #牛牛学数列3#
牛牛学数列3
https://www.nowcoder.com/practice/f65c726d081c4160a9356eabf0dc21d9
#include <stdio.h>
#include <math.h>
int main()
{
int a;
double sum = 0;
scanf("%d", &a);
for(int i = 1; i<=a;i++)
{
int sum1 = pow(-1,i-1)*(2*i-1) + sum1;
sum += 1.0/sum1;
}
printf("%.3lf", sum);
return 0;
}
