更新1:
謝謝
條件如圖，請問如何求出x?
回答 (2)
2016-02-03 2:04 pm
✔ 最佳答案
2log2/logx=log2x/log2=(log2+logx)/log2交叉相乘得 logx(log2+logx)=2(log2)^2
(logx)^2+log2logx-2(log2)^2=(logx-log2)(logx+2log2)=0
logx=log2, x=2(不合), logx= -2log2=log2^(-2)=log(1/4), x=1/4
2016-02-13 7:54 am
設y=log x/log 2
2/y=1+y
2=y+y^2
y^2+y-2=0
y=1 or y=-2
log x/log 2=1 log x/log 2=-2
x=2(delete) or x=0.25
2/y=1+y
2=y+y^2
y^2+y-2=0
y=1 or y=-2
log x/log 2=1 log x/log 2=-2
x=2(delete) or x=0.25
收錄日期: 2021-04-18 14:25:17
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160203053046AAPp8xV