1
----------
/ 2\
| x |
7*|1 + --|
\ 49/
$$\frac{1}{\frac{x^{2}}{7} + 7}$$
-2*x
-------------
2
/ 2\
| x |
343*|1 + --|
\ 49/
$$- \frac{2 x}{343 \left(\frac{x^{2}}{49} + 1\right)^{2}}$$
/ 2 \
| 4*x |
14*|-1 + -------|
| 2|
\ 49 + x /
-----------------
2
/ 2\
\49 + x /
$$\frac{\frac{56 x^{2}}{x^{2} + 49} - 14}{\left(x^{2} + 49\right)^{2}}$$