Question
If f(x)= \begin{cases} \log_{2}x &(x>0) \\ 2^x &(x\leq 0) \end{cases}
find the value of f[f(\frac{1}{9})]
Answer
When x=\dfrac{1}{9}>0
f(\dfrac{1}{9} )=\log_{2}\dfrac{1}{9} <0
f[f(\frac{1}{9})]=2^{\log_{2}\frac{1}{9} }=\dfrac{1}{9}