Question

有数列2/3 .4/5 .6/9. 10/15 .求此数列前30项的和编程

Answer 1

#include<stdio.h>

int main()
{
        double x1=2,x2=4;
        double y1=3,y2=5;
        double temp1,temp2;
        double sum = 0;
        int i;
        sum += (x1/y1);
        for(i=0;i<29;i++)
        {
                sum += (x2/y2);
                temp1 = x1+x2;
                temp2 = x2+y2;
                x1 = x2;
                y1= y2;
                x2 = temp1;
                y2 = temp2;
        }
        printf("the result is %f\n",sum);
}

Answer 2

分子是前两项只和，分母是前一项分子与分母之和