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问题: 高一数学

(0.135)的x次=(13.5)的y次=100
则1/x-1/y=

解答:

0.135^x =100 ==> x*lg0.135 =2 ...(1)
13.5^y =100 ==> y*lg13.5 =2 ...(2)
(1)/2x -(2)/2y
==> 1/x -1/y =(lg0.135-lg13.5)/2 = -1