I would like some more feedback?

Question

on this question I asked yesterday. What do you think?

http://answers.yahoo.com/question/index;_ylt=AiqUuSnFymlPCcSbQrSoKYnsy6IX;_ylv=3?qid=20071102052735AAmwevZ

Answer 1

If the second derivative has the occasionally 0 point in an interval where it's otherwise negative, that surely doesn't keep the function from being concave down.

If you have a weird situation where the first derivative is decreasing, then constant for a while, and then decreases again -- well, I'd still call that "concave down", but I wouldn't argue hard for my point.