if x^2+y^2=-xy, show that log(x+y)=1/2(logx+logy)
thx!
(急!!) F.4 maths log
2010-08-10 2:56 am
回答 (1)
2010-08-10 4:10 am
✔ 最佳答案
x^2+y^2=-xy(x+y)^2-2xy=-xy
(x+y)^2=xy
Take log on both sides,
log[(x+y)^2]=logxy
2log(x+y)=logx+logy
log(x+y)=(1/2)(logx+logy)
收錄日期: 2021-04-22 00:49:43
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100809000051KK01425