Re: [中學] 對數
: 抱歉想問這題 感謝
(2log2 + logx)(log2 - logx) = 1
(logx)^2 + (log2)(logx) + 1 - 2(log2)^2 = 0
x_1, x_2為兩實根
logx_1 + logx_2 = log(x_1 x_2) = -log2
=> x_1 x_2 = 1/2
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抱歉 多打一個2
※ 編輯: Honor1984 (111.249.191.221), 12/29/2016 00:32:11
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