acos(1 - 3*x)
3 ------------------- ________________ / 2 \/ 1 - (1 - 3*x)
9*(-1 + 3*x) ------------------- 3/2 / 2\ \1 - (1 - 3*x) /
/ 2 \ | 3*(-1 + 3*x) | 27*|1 + --------------| | 2| \ 1 - (1 - 3*x) / ----------------------- 3/2 / 2\ \1 - (1 - 3*x) /