Higher Derivative Test
Suppose:
$$f'(c)=f''(c)=\cdots=f^{(n-1)}(c)=0$$
but:
$$f^{(n)}(c)\neq0$$
If $$n$$ is even and:
$$f^{(n)}(c)>0$$
then $$f(c)$$ is a local minimum.
If $$n$$ is even and:
$$f^{(n)}(c)<0$$
then $$f(c)$$ is a local maximum.
Usage
- Used when several successive derivatives vanish at a stationary point.