acos(4*x)
-4 -------------- ___________ / 2 \/ 1 - 16*x
-64*x -------------- 3/2 / 2\ \1 - 16*x /
/ 2 \ | 48*x | -64*|1 + ---------| | 2| \ 1 - 16*x / ------------------- 3/2 / 2\ \1 - 16*x /