一道SAT数学题,好久没学数学了,忘了改咋做forallpositiveintegersx,thefunctionfisdefinedbyf(x)=(1/a^4)^x,whereaisaconstantgreaterthan1.Whichofthefollowingisequivalenttof(2x)A、1/2f(x)B、2f(x)C、4f(x)D、（f(x)

Question

一道SAT数学题,好久没学数学了,忘了改咋做
for all positive integers x,the function f is defined by f(x)=(1/a^4)^x,where a is a constant greater than 1.Which of the following is equivalent to f(2x)
A、1/2f(x)
B、2f(x)
C、4f(x)
D、（f(x)）^2
E、√f(x)

Answer 1

这个题一看就是D嘛