(一)有已知得f(x)=3的X次方,f(y)=3的y次方,
则f(x)*f(y)=3^x(3的x次方)*3^y=3^(x+y)=f(x+y)
f(x)/f(y)=3^x/3^y=3^x * 3^(-y)=3^(x-y)=f(x-y)