Mathematics

Problem

Which of the following best describes a critical point of a real-valued function

f

defined on an open interval? a) A point

c

where

f'(c)=0

b) A point

c

where

f(c)

attains a maximum or minimum value c) A point

c

where

f'(c)=0

f'

is not defined at

c

d) A point

c

where

f''(c)=0