1、a^(log(a)(b))=b 　　
2、log(a)(MN)=log(a)(M)+log(a)(N); 　　
3、log(a)(M÷N)=log(a)(M)-log(a)(N); 　　
4、log(a)(M^n)=nlog(a)(M) 　　
5、log(a^n)(M)=1/nlog(a)(M)