Moderate# How Many Critical Points: Cosine Function

APCALC-GK44T8

The derivative of a function $g$ is given by,

$$g'(x) = \cos \left( {{{\left( {x - \frac{\pi }{2}} \right)}^x}} \right)$$

How many critical points does the function $g(x)$ have on the interval $[1.8, 3.7]$?