今天吃飯時，想到1/2 + 1/3 + 1/6 = 1,於是想到分母從3，4開始，即1/3, 1/4, 第3個分母是前面兩個分母的乘積，即 1/3 + 1/4 + ...... + 1/n,當n等於多少時，和爲1呢？於是用代碼去算：
int a = 3, b =4;
double sum = 0;
double counts = 10000000000000000000000d;
for(int c = 0; c < counts; c++) {
c = a * b;
b= c;
System.out.println("c = " + c + "||" + "b = " + b);
sum = (1/a) + (1/b) +(1/c);
System.out.println("sum = " + sum);
if(sum == 1) {
System.out.println("c = " + c);
break;
}
}
}
public static void main(String[] args) {
guessfun();
}
}
結果是一直運算也得不到，然後一查，居然是調和級數的引用。