1/(1/20+1/21+1/22+1/23+...+1/38+1/39)

题目

1/(1/20+1/21+1/22+1/23+...+1/38+1/39)
的整数部分是多少?

答案

double c = 20;
double sum = 0;
for (int i = 0; i < 19; i++)
{
sum += 1 / (c + i);
}
Console.WriteLine(1/sum);
1.47023720286133
应该是1吧