$$1 - \frac{2}{4 x^{2} + 1}$$
16*x
-----------
2
/ 2\
\1 + 4*x /
$$\frac{16 x}{\left(4 x^{2} + 1\right)^{2}}$$
/ 2 \
| 16*x |
16*|1 - --------|
| 2|
\ 1 + 4*x /
-----------------
2
/ 2\
\1 + 4*x /
$$\frac{- \frac{256 x^{2}}{4 x^{2} + 1} + 16}{\left(4 x^{2} + 1\right)^{2}}$$