#include <stdio.h>
#include <stdlib.h>
#define PI 3.14159

//a(n) = PI*(3/5)**(n-1)

long double sumSeries(int n)
{
 int i;
 long double res = PI;
 long double sum = 0;
 for (i = 0; i <= n; i++)
 {
  sum = sum + res ;
  res = res * (3.0/5.0);
 }


 return sum;

}

void main(void) {
 for (int n = 10; n <= 10000; n=n*10) {
  printf("n = %d = %lf\n",n,sumSeries(n));

 }
 system("pause");

}


//a(n) = PI*(3/5)^(n-1)

n=10,100,1000,1000 ...  일때 등비수열의합을 구하는건데요


이클립스로 돌리는데 계속

n = 10 = -478133174482612520000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000
n = 100 = -11755285026247699000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000
n = 1000 = -11755285026247699000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000
n = 10000 = -11755285026247699000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000


이런식으로 -가 붙어서 나오네요 ㅠㅠ 100넘어가면 값도 똑같고 어떻게 고치나요?