Question

数列问题！！急！

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？

Answer 1

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

Answer 2

2dx+1(d为倒数的等差)

Answer 3

1/x-1/y=1/y-1/z
x-y/y-z=x/z