/ 1 -4 + x \ /-4 + x\
|----- - --------|*sign|------|
|4 + x 2| \4 + x /
\ (4 + x) /
-------------------------------
|x - 4|
|-----|
|x + 4|
$$\frac{\left(- \frac{x - 4}{\left(x + 4\right)^{2}} + \frac{1}{x + 4}\right) \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)}}{\left|{\frac{x - 4}{x + 4}}\right|}$$
/ /-4 + x\ 2/-4 + x\ / -4 + x\\
| 2*sign|------| sign |------|*|-1 + ------||
/ -4 + x\ | d / /-4 + x\\ \4 + x / \4 + x / \ 4 + x /|
|-1 + ------|*|- --|sign|------|| + -------------- - ---------------------------|
\ 4 + x / | dx\ \4 + x // 4 + x |-4 + x| |
| (4 + x)*|------| |
\ |4 + x | /
---------------------------------------------------------------------------------
|-4 + x|
(4 + x)*|------|
|4 + x |
$$\frac{\left(\frac{x - 4}{x + 4} - 1\right) \left(- \frac{d}{d x} \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)} - \frac{\left(\frac{x - 4}{x + 4} - 1\right) \operatorname{sign}^{2}{\left(\frac{x - 4}{x + 4} \right)}}{\left(x + 4\right) \left|{\frac{x - 4}{x + 4}}\right|} + \frac{2 \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)}}{x + 4}\right)}{\left(x + 4\right) \left|{\frac{x - 4}{x + 4}}\right|}$$
/ 2 \
| /-4 + x\ d / /-4 + x\\ / -4 + x\ 3/-4 + x\ 2/-4 + x\ / -4 + x\ / -4 + x\ d / /-4 + x\\ /-4 + x\|
| 2 6*sign|------| 4*--|sign|------|| 2*|-1 + ------| *sign |------| 6*sign |------|*|-1 + ------| 3*|-1 + ------|*--|sign|------||*sign|------||
/ -4 + x\ | d / /-4 + x\\ \4 + x / dx\ \4 + x // \ 4 + x / \4 + x / \4 + x / \ 4 + x / \ 4 + x / dx\ \4 + x // \4 + x /|
|-1 + ------|*|- ---|sign|------|| - -------------- + ------------------ - ------------------------------ + ----------------------------- - ---------------------------------------------|
\ 4 + x / | 2\ \4 + x // 2 4 + x 2 2 |-4 + x| |-4 + x| |
| dx (4 + x) 2 |-4 + x| (4 + x) *|------| (4 + x)*|------| |
| (4 + x) *|------| |4 + x | |4 + x | |
\ |4 + x | /
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|-4 + x|
(4 + x)*|------|
|4 + x |
$$\frac{\left(\frac{x - 4}{x + 4} - 1\right) \left(- \frac{d^{2}}{d x^{2}} \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)} - \frac{3 \left(\frac{x - 4}{x + 4} - 1\right) \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)} \frac{d}{d x} \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)}}{\left(x + 4\right) \left|{\frac{x - 4}{x + 4}}\right|} + \frac{4 \frac{d}{d x} \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)}}{x + 4} - \frac{2 \left(\frac{x - 4}{x + 4} - 1\right)^{2} \operatorname{sign}^{3}{\left(\frac{x - 4}{x + 4} \right)}}{\left(x + 4\right)^{2} \left|{\frac{x - 4}{x + 4}}\right|^{2}} + \frac{6 \left(\frac{x - 4}{x + 4} - 1\right) \operatorname{sign}^{2}{\left(\frac{x - 4}{x + 4} \right)}}{\left(x + 4\right)^{2} \left|{\frac{x - 4}{x + 4}}\right|} - \frac{6 \operatorname{sign}{\left(\frac{x - 4}{x + 4} \right)}}{\left(x + 4\right)^{2}}\right)}{\left(x + 4\right) \left|{\frac{x - 4}{x + 4}}\right|}$$