Application Of Derivatives

$f$ is increasing on $\left(\frac{\pi}{4}, \frac{\pi}{2}\right)$.

$f$ is decreasing on $\left(\frac{\pi}{4}, \frac{\pi}{2}\right)$

$f$ is increasing on $\left(\frac{\pi}{4}, \frac{\pi}{3}\right)$ and decreasing on $\left(\frac{\pi}{3}, \frac{\pi}{2}\right)$.

$f$ is decreasing on $\left(\frac{\pi}{4}, \frac{\pi}{3}\right)$ and increasing on $\left(\frac{\pi}{3}, \frac{\pi}{2}\right)$.