1Q of F.5 maths
回答 (1)
2011-07-21 5:16 am
✔ 最佳答案
Let log(base 3)x = log x/log 3 = y.So log (base x)3 = log 3/log x = 1/y
So the equation becomes
y - 3/y = 2
y^2 - 3 = 2y
y^2 - 2y - 3 = 0
(y - 3)(y + 1) = 0
y = 3 or - 1
(a) y = log x/log 3 = 3
log x = 3 log 3 = log 3^3 = log 27
x = 27.
(b) log x/log 3 = - 1
log x = - log 3 = log 3^(-1) = log 1/3
x = 1/3.
收錄日期: 2021-04-25 22:38:34
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https://hk.answers.yahoo.com/question/index?qid=20110720000051KK01081