Originally Posted by

**tiar** Hi, I'm very uncertain of what to do here:

$\displaystyle Let f(x) = log_{2} (x)$

$\displaystyle g(x) = sin (\frac{\pi}{2} x)$

$\displaystyle h(x) =\left\{\begin{array}{cc}2^{-x},& \mbox{ if } x>0\\-3x^2 - 4x +1, &\mbox{ if }x\leq 0\end{array}\right.$

*Evaluate the following: *

*(a) (h o f) (4)*

*(b) (g/h)(0)*

For the piece-wise defined function, h(x), how can I determine which one to use?

I tried (h o f)(4), but I'm not certain on it at all:

$\displaystyle

(h o f)(4) = log_{2}(2^{-4})$

$\displaystyle

(h o f)(4) = -4

$

Am I anywhere close? Or did I not plug them into each other correctly?

These confuse me so much.

Thanks in advanced!