/ 2 2 2 \
| 2 acos (7*x) 147*x *acos (7*x) 42*x*acos(7*x)|
1029*|- -------------- - -------------- - ----------------- + --------------|
| 3/2 3/2 5/2 2 |
| / 2\ / 2\ / 2\ / 2\ |
\ \1 - 49*x / \1 - 49*x / \1 - 49*x / \-1 + 49*x / /
$$1029 \left(- \frac{147 x^{2} \operatorname{acos}^{2}{\left(7 x \right)}}{\left(1 - 49 x^{2}\right)^{\frac{5}{2}}} + \frac{42 x \operatorname{acos}{\left(7 x \right)}}{\left(49 x^{2} - 1\right)^{2}} - \frac{\operatorname{acos}^{2}{\left(7 x \right)}}{\left(1 - 49 x^{2}\right)^{\frac{3}{2}}} - \frac{2}{\left(1 - 49 x^{2}\right)^{\frac{3}{2}}}\right)$$