x,y,z的倒数为等差数列,且x,y,z互不相等,求x-y/y-z等于?
问题描述：
x,y,z的倒数为等差数列,且x,y,z互不相等,求x-y/y-z等于?
答
2dx+1(d为倒数的等差)
答
x，y，z的倒数为等差数列
1/x=a-d x=1/(a-d)
1/y=a y=1/a
1/z=a+d z=1/(a+d)
x-y/y-z
=(1/(a-d)-1/a)/(1/a-1/(a+d))
=(a+d)/(a-d) 值不定
x=1/2 y=1/3 z=1/4 倒数为2,3,4等差数列，x-y/y-z=2
x=1/3 y=1/4 z=1/5 倒数为3,4,5等差数列，x-y/y-z=5/4
答
1/x-1/y=1/y-1/z
x-y/y-z=x/z