/ 2\ acos\1 - x /
acos(1 - x^2)
2*x ------------------- _______________ / 2 / / 2\ \/ 1 - \1 - x /
/ 2 / 2\\ | 2*x *\-1 + x /| 2*|1 + --------------| | 2 | | / 2\ | \ 1 - \1 - x / / ---------------------- _______________ / 2 / / 2\ \/ 1 - \1 - x /
/ 2\ | 2 / 2\ | | 2 6*x *\-1 + x / | 4*x*|-3 + 5*x + ---------------| | 2 | | / 2\ | \ 1 - \1 - x / / --------------------------------- 3/2 / 2\ | / 2\ | \1 - \1 - x / /