$$\frac{4 x}{4 x^{4} + 1}$$
/ 4 \
| 16*x |
4*|1 - --------|
| 4|
\ 1 + 4*x /
----------------
4
1 + 4*x $$\frac{- \frac{64 x^{4}}{4 x^{4} + 1} + 4}{4 x^{4} + 1}$$
/ 4 \
3 | 32*x |
64*x *|-5 + --------|
| 4|
\ 1 + 4*x /
---------------------
2
/ 4\
\1 + 4*x / $$\frac{64 x^{3}}{\left(4 x^{4} + 1\right)^{2}} \left(\frac{32 x^{4}}{4 x^{4} + 1} - 5\right)$$