Results 1 to 4 of 4

- May 12th 2010, 03:24 AM #1

- Joined
- Nov 2007
- Posts
- 15

- May 12th 2010, 10:52 AM #2

- May 14th 2010, 12:56 AM #3

- Joined
- Nov 2007
- Posts
- 15

- May 14th 2010, 01:46 AM #4
The only reason that you need the condition f''(x)>0 (for x>0) is that it implies that f'(x) is a strictly increasing function, so that f'(x+y) > f'(x) when y>0.

The value of f''(x) when x=0 is not relevant. The fact that f''(x) > 0 when x>0 does in fact imply that f is strictly convex.