#include <stdio.h>
 
double calculate_series(int n) {
    double sum = 0.0; // 級数の和
 
    for (int k = 1; k <= n; k++) {
        sum += 1.0 / (k * (k + 1)); // 各項を計算して加算
    }
 
    return sum;
}
 
int main() {
    int n1 = 3, n2 = 10; // 計算対象の n の値
    double result1, result2;
 
    // n=3 のときの計算
    result1 = calculate_series(n1);
    printf("n = %d のとき、x(n) = %.6f\n", n1, result1);
 
    // n=10 のときの計算
    result2 = calculate_series(n2);
    printf("n = %d のとき、x(n) = %.6f\n", n2, result2);
 
    return 0;
}
 

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