Which one of the following real-valued functions on is NOT injective?

MATHEMATICS · Single correct · A Level · Mathematics · Algebra and Functions · Algebra and Functions

Problem

Which one of the following real-valued functions on

\mathbb R

is NOT injective? (a)

f(x)=x^3

(b)

h(x)=|x|

(c)

g(x)=\sqrt[3]{x}

(d)

p(x)=\tan^{-1}x