/ 2 2 2 \
| 2 acos (3*x) 27*x *acos (3*x) 18*x*acos(3*x)|
81*|- ------------- - ------------- - ---------------- + --------------|
| 3/2 3/2 5/2 2 |
| / 2\ / 2\ / 2\ / 2\ |
\ \1 - 9*x / \1 - 9*x / \1 - 9*x / \-1 + 9*x / /
$$81 \left(- \frac{27 x^{2} \operatorname{acos}^{2}{\left (3 x \right )}}{\left(- 9 x^{2} + 1\right)^{\frac{5}{2}}} + \frac{18 x \operatorname{acos}{\left (3 x \right )}}{\left(9 x^{2} - 1\right)^{2}} - \frac{\operatorname{acos}^{2}{\left (3 x \right )}}{\left(- 9 x^{2} + 1\right)^{\frac{3}{2}}} - \frac{2}{\left(- 9 x^{2} + 1\right)^{\frac{3}{2}}}\right)$$