how to prove x^(1/2)>In x when x>0
可唔可以教下我 thx
the exopnential and log funtion
2008-04-21 7:42 pm
回答 (2)
2008-04-21 7:51 pm
✔ 最佳答案
Let f(x) = x^(1/2) - In xd(f(x))/dx = 1/2/ x^(1/2) - 1/x
=[x^(1/2)-2]/[2x]
d(f(x))/dx =0 when x=4
and after verification, f(x) attains minimum at x=4
since f(4) = 2-ln2 >0 and f(x) >=f(4)
therefore x^(1/2) - In x >0 when x>0
2008-04-22 7:09 pm
thx
收錄日期: 2021-04-26 13:57:26
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080421000051KK00659