用另外一个换底公式,lgb/lga*lga/lgb不是等于lg1吗?怎么等于的1问题中的方框是乘
loga(b)*logb(a)
=loga(b)*loga(a) /loga(b)
=loga(a)
=1
对数的运算法则:
1、log(a) (M·N)=log(a) M+log(a) N
2、log(a) (M÷N)=log(a) M-log(a) N
3、log(a) M^n=nlog(a) M
4、log(a)b*log(b)a=1
5、log(a) b=log (c) b÷log (c) a