Recall that an exponential function:
[tex]f(x)=k^x,[/tex]
is increasing if k>1 and decreasing if 0
Therefore:
[tex]f(x)=(\frac{1}{4})^x,\text{ }f(x)=(\frac{1}{2})^x,\text{ and }f(x)=(0.4)^2[/tex]
are decreasing functions and
[tex]f(x)=4^x[/tex]
is an increasing function.
Answer: Option C.
