則log 開方 x^2 -y^2= ?
p.s.開方成舊的
更新1:
thx,天日比你5分^^
maths log 問題
回答 (1)
2008-03-05 7:15 am
✔ 最佳答案
log(x＋y)=alog(x-y)=b
log { x^2 -y^2 }^1/2 因 log x^y = y log x
=1/2 log { x^2 -y^2 } 因 x^2-y^2 = (x＋y)(x-y)
=1/2 log { (x＋y)(x-y) } 因 log a*b = loga＋logb
=1/2 { log(x＋y) ＋ log(x-y) }
=1/2 ( a＋b )#
收錄日期: 2021-04-23 17:45:25
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080304000051KK03300