\[\](1)an increasing function in $( 0 ,\frac{\pi}{2})$\[\](2)an decreasing function in $(0 ,\frac{\pi}{2})$\[\](3)increasing in $(0 ,\frac{\pi}{4})$decreasing in $(\frac{\pi}{4} ,\frac{\pi}{2})$\[\](4)decreasing in $(0 ,\frac{\pi}{4})$ increasing in $(\frac{\pi}{4} ,\frac{\pi}{2}$)
