First derivative test for local extrema
The First Derivative Test for Local Extrema states that if is a critical point of a continuous function , and if is differentiable at every point in some interval containing except possibly at itself, then
- If changes from negative to positive at , then has a local minimum at .
- If changes form positive to negative at , then has a local maximum at .
- If does not change sign at , then has no local extremum at .
Developed for use with Thomas' Calculus, published by Pearson.