2/x\
-acos |-|
\3/
-------------
________
/ 2
/ x
/ 1 - --
\/ 9
$$- \frac{\operatorname{acos}^{2}{\left(\frac{x}{3} \right)}}{\sqrt{- \frac{x^{2}}{9} + 1}}$$
/ /x\ \
| x*acos|-| |
| 54 \3/ | /x\
-|------- + -----------|*acos|-|
| 2 3/2| \3/
|-9 + x / 2\ |
| | x | |
| |1 - --| |
\ \ 9 / /
---------------------------------
9
$$- \frac{\left(\frac{x \operatorname{acos}{\left(\frac{x}{3} \right)}}{\left(- \frac{x^{2}}{9} + 1\right)^{\frac{3}{2}}} + \frac{54}{x^{2} - 9}\right) \operatorname{acos}{\left(\frac{x}{3} \right)}}{9}$$
/ 2/x\ \ / 2 2/x\\
| acos |-| | |x *acos |-||
| \3/ | | \3/|
|-----------| |-----------|
| 3/2| | 5/2|
|/ 2\ | |/ 2\ |
|| x | | || x | | /x\
||1 - --| | ||1 - --| | x*acos|-|
2 \\ 9 / / \\ 9 / / \3/
- ------------- - ------------- - ------------- + 18*----------
3/2 9 27 2
/ 2\ / 2\
| x | \-9 + x /
9*|1 - --|
\ 9 /
$$18 \frac{x \operatorname{acos}{\left(\frac{x}{3} \right)}}{\left(x^{2} - 9\right)^{2}} - \frac{x^{2} \frac{1}{\left(- \frac{x^{2}}{9} + 1\right)^{\frac{5}{2}}} \operatorname{acos}^{2}{\left(\frac{x}{3} \right)}}{27} - \frac{\frac{1}{\left(- \frac{x^{2}}{9} + 1\right)^{\frac{3}{2}}} \operatorname{acos}^{2}{\left(\frac{x}{3} \right)}}{9} - \frac{2}{9 \left(- \frac{x^{2}}{9} + 1\right)^{\frac{3}{2}}}$$