How would I simplifiy this fraction with exponents? How would I simplify this:
$$
\frac{\eta^{k-2}}{\eta_c^k}
$$
so that $\eta_c$ can also be raised to the power of $k-2$?
Would there be an $\eta_c^2$ on the top or bottom?

You could simplify it as:
$$\left(\frac{\eta}{\eta_c} \right)^{k-2}\cdot\frac{1}{\eta_c^2}$$
In other words, it would go at the bottom.
