loga(MN)=logaM+logaN；
loga(M/N)=logaM－logaN；
loga(M^n)=nlogaM；
a^(log(a)(b))=b
log(a)(MN)=log(a)(M)+log(a)(N);
log(a)(M÷N)=log(a)(M)-log(a)(N);
log(a)(M^n)=nlog(a)(M)
log(a^n)M=1/nlog(a)(M)
自然對數(shù)與換底公式：