对数函数问题
问题描述：
对数函数问题
log18 9 = a log18 5 =b 则log36 45=
用a b表示?
y=log2 (x^2-ax-a)在x小于 一减根号3 上是增函数 则a的取值范围?
答
log18 (9 ) = a,即log18 (18/2) = a,1- log18 (2) = a,log18 (2) =1-a.log36( 45)= log18 (45)/ log18 (36)=[ log18 (9 )+ log18 (5)]/[ log18 (18×2)]=[ log18 (9 )+ log18 (5)]/ [ log18 (18)+ log18 (2)]=(a+b)/...