we have the function
[tex]f(x)=\frac{5}{4}\sin x+1[/tex]Part 1
the maximum value of the function is 2.25
For x=pi/2
[tex]\begin{gathered} f(\frac{\pi}{2})=\frac{5}{4}\sin \frac{\pi}{2}+1 \\ f(\frac{\pi}{2})=\frac{5}{4}+1 \\ f(\frac{\pi}{2})=2.25 \end{gathered}[/tex]Part 2
The minimum value of the function is -0.25
For x=-pi/2
[tex]\begin{gathered} f(-\frac{\pi}{2})=\frac{5}{4}\sin \frac{-\pi}{2}+1 \\ f(-\frac{\pi}{2})=-\frac{5}{4}+1 \\ f(-\frac{\pi}{2})=-0.25 \end{gathered}[/tex]Part 3
over the interval [0,pi/2] the function is increasing
Part 4
the range of the function is the interval [-0.25, 2.25]