log(a,9)=2 [以a為底，真數9的對數是2]
a=3
f(x)=log(3,x)
f(-1)x=3^x [f(x)的反函數是3^x]
f-1(log(9,2)=3^(log(9,2))=[9^(log(9,2)]^(1/2)=2^(1/2)
答案A √2
log(a,9)=2 [以a為底，真數9的對數是2]
a=3
f(x)=log(3,x)
f(-1)x=3^x [f(x)的反函數是3^x]
f-1(log(9,2)=3^(log(9,2))=[9^(log(9,2)]^(1/2)=2^(1/2)
答案A √2