acos(5*x)
-5 -------------- ___________ / 2 \/ 1 - 25*x
-125*x -------------- 3/2 / 2\ \1 - 25*x /
/ 2 \ | 75*x | -125*|1 + ---------| | 2| \ 1 - 25*x / -------------------- 3/2 / 2\ \1 - 25*x /