If is twice differentiable and for all in the interval

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

Problem

f

is twice differentiable and

f''(x)>0

for all

x

in the interval

(2,5)

, which of the following statements about the graph of

f

(2,5)

is correct? (a)

f

has an inflection point at

x=3.5

(2,5)

. (b) The graph of

f

is concave down on

(2,5)

. (c) The graph of

f

is concave up on

(2,5)

. (d) The graph of

f

is increasing on

(2,5)