/ 20*cos(4*x) 125*x*sin(4*x)\
2*|-8*atan(5*x)*sin(4*x) + ----------- - --------------|
| 2 2 |
| 1 + 25*x / 2\ |
\ \1 + 25*x / /
$$2 \left(- \frac{125 x \sin{\left(4 x \right)}}{\left(25 x^{2} + 1\right)^{2}} - 8 \sin{\left(4 x \right)} \operatorname{atan}{\left(5 x \right)} + \frac{20 \cos{\left(4 x \right)}}{25 x^{2} + 1}\right)$$
/ / 2 \ \
| | 100*x | |
| 125*|-1 + ---------|*sin(4*x)|
| | 2| |
| 120*sin(4*x) 1500*x*cos(4*x) \ 1 + 25*x / |
2*|- ------------ - 32*atan(5*x)*cos(4*x) - --------------- + -----------------------------|
| 2 2 2 |
| 1 + 25*x / 2\ / 2\ |
\ \1 + 25*x / \1 + 25*x / /
$$2 \left(- \frac{1500 x \cos{\left(4 x \right)}}{\left(25 x^{2} + 1\right)^{2}} - 32 \cos{\left(4 x \right)} \operatorname{atan}{\left(5 x \right)} - \frac{120 \sin{\left(4 x \right)}}{25 x^{2} + 1} + \frac{125 \left(\frac{100 x^{2}}{25 x^{2} + 1} - 1\right) \sin{\left(4 x \right)}}{\left(25 x^{2} + 1\right)^{2}}\right)$$