指數對數的題目求解?
回答 (1)
2016-10-25 8:13 am
✔ 最佳答案
Sollogx_27－2log3_x=5
log27/logx－2logx/log3=5
Set p=logx
3log3/p－2p/log3=5
3(log3)^2－2p^2=5log3p
2p^2－5log3p－3(log3)^2=0
(2p+log3)(p－3log3)=0
p=－log3/2 or p=3log3
(1)
p=－log3/2
logx=－log3/2
2logx=－log3
x^2=1/3
x=√3/3 (負不合
(2)
p=3log3
logx=log27
x=27
收錄日期: 2021-04-30 21:54:38
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20161024232115AAojeJB