1: f ''(x) is negative, if f '(x) is ____

2: If f (x) is concave up, then f '(x) is ___

3: If f (x) has an inflection point at x = a, then f (x) has a ______ maximum minimum horizontal tangent change in concavity at x = a.

4: If f ''(x) has a change in sign and is always defined, then f '(x) has a ____