The attached table is one that it is convenient for you to memorize as long as you're taking courses involving angles. For the inverse functions, find the column corresponding to the function, then look for the value in that column. The angle at the beginning of that row is the answer to your question.
8. [tex]\cos^{-1}(0)= 90^{\circ}=\dfrac{\pi}{2}[/tex]
9. [tex]\sin^{-1}(1)= 90^{\circ}=\dfrac{\pi}{2}[/tex]
10. [tex]\tan^{-1}\left( \dfrac{\sqrt{3}}{3} \right)=30^{\circ}=\dfrac{\pi}{6}[/tex]
