acos(3*x)
d --(acos(3*x)) dx
-3 ------------- __________ / 2 \/ 1 - 9*x
-27*x
-------------
3/2
/ 2\
\1 - 9*x /
/ 2 \
| 27*x |
-27*|1 + --------|
| 2|
\ 1 - 9*x /
------------------
3/2
/ 2\
\1 - 9*x /