Question

Let f(x)=−x4−9x3+3x−2f(x)=−x4−9x3+3x−2. Find the open intervals on which ff is concave up (down). Then determine the xx-coordinates of all inflection points of ff.

1.	ff is concave up on the intervals------------------
2.	ff is concave down on the intervals---------------
3.	The inflection points occur at xx =----------------

Notes: In the first two, your answer should either be a single interval, such as (0,1), a comma separated list of intervals, such as (-inf, 2), (3,4), or the word "none".

In the last one, your answer should be a comma separated list of xx values or the word "none".