Finding Where F is concave up/down using the graph of the first derivative

[Econometricia]

1. I need to find where the graph of f is CU or CD given the graph of f ' .



2. So far I have found that F inc. on (2,4) and (6,9). F has a local max at 4. F has a local min at 2 and 6.

 

[Tinyboss]

When f' is increasing, i.e. when f''>0, f is concave up, and conversely.

 

[MitsuShai]

you have to find f '' then you can judge concavity
if f'' is bigger than 0 then it's concave up if f'' is smaller than 0 than it is concave down