/ 2 \
| 1 36*x 9*x |
54*|-1 + --------------------- + -------- + --------------------|
| / 2\ 2 2 / 2\ |
\ \1 + 9*x /*atan (3*x) 1 + 9*x \1 + 9*x /*atan(3*x)/
-----------------------------------------------------------------
2
/ 2\
\1 + 9*x / *atan(3*x)
$$\frac{1}{\left(9 x^{2} + 1\right)^{2} \operatorname{atan}{\left (3 x \right )}} \left(\frac{1944 x^{2}}{9 x^{2} + 1} + \frac{486 x}{\left(9 x^{2} + 1\right) \operatorname{atan}{\left (3 x \right )}} - 54 + \frac{54}{\left(9 x^{2} + 1\right) \operatorname{atan}^{2}{\left (3 x \right )}}\right)$$