2*x*asin(x)
2*x 2*asin(x) + ----------- ________ / 2 \/ 1 - x
/ 2 \ | x | 2*|2 + ------| | 2| \ 1 - x / -------------- ________ / 2 \/ 1 - x
/ 2 \ | 3*x | 2*x*|4 + ------| | 2| \ 1 - x / ---------------- 3/2 / 2\ \1 - x /