$$\frac{6}{4 x^{2} + 1}$$
-48*x
-----------
2
/ 2\
\1 + 4*x /
$$- \frac{48 x}{\left(4 x^{2} + 1\right)^{2}}$$
/ 2 \
| 16*x |
48*|-1 + --------|
| 2|
\ 1 + 4*x /
------------------
2
/ 2\
\1 + 4*x /
$$\frac{\frac{768 x^{2}}{4 x^{2} + 1} - 48}{\left(4 x^{2} + 1\right)^{2}}$$