指數(shù)函數(shù)：y=f(x)=a^x
f(m)*f(n)=(a^m)*(a^n)=a^(m+n)
[f(m)]^n==(a^m)^n=a^(m*n)
lgy=lga^x=xlga
lg[f(m)*f(n)]=lg[(a^m)*(a^n)]=lg[a^(m+n)]=(m+n)lga
lg[f(m)]^n==lg[(a^m)^n]=lga^(m*n)=m*n*lga
冪函數(shù)：y=x^a