How many critical points does the function $f(x)=2si{n}^2(3x)$ have on the interval $(0,)?$ Provide the $x$ coordinate for each of the first $2$ critical points below in increasing order. Note that the interval does not include $0$ or $.$

Include a multiplication sign between terms $($e$.$g$.3^{**}x).$ Type Pi for $.$

Number of critical points: $$

First critical point

$a^b$

$sin(a)$

$$

$$

$(?)$

Second critical point: