Which of the following best defines a critical number of a function on an interval ?

MATHEMATICS · Single correct · A Level · Mathematics · Differentiation · Differentiation

Problem

Which of the following best defines a critical number of a function

f

on an interval

I

? (a) A value

c

in the domain of

f

where

f'(c)=0

. (b) A value

c

in the domain of

f

where

f'(c)=0

f'(c)

does not exist. (c) A value

c

in the interval

I

where

f

attains a local maximum. (d) A value

c

in the domain of

f

where

f''(c)=0

and

f

is twice–differentiable on

I