2
-21*x
---------
6
1 + 49*x
$$- \frac{21 x^{2}}{49 x^{6} + 1}$$
/ 6 \
| 147*x |
42*x*|-1 + ---------|
| 6|
\ 1 + 49*x /
---------------------
6
1 + 49*x
$$\frac{42 x}{49 x^{6} + 1} \left(\frac{147 x^{6}}{49 x^{6} + 1} - 1\right)$$
/ 12 6 \
| 86436*x 1323*x |
42*|-1 - ------------ + ---------|
| 2 6|
| / 6\ 1 + 49*x |
\ \1 + 49*x / /
----------------------------------
6
1 + 49*x
$$\frac{1}{49 x^{6} + 1} \left(- \frac{3630312 x^{12}}{\left(49 x^{6} + 1\right)^{2}} + \frac{55566 x^{6}}{49 x^{6} + 1} - 42\right)$$