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The function $f: \mathbb{R} \to \mathbb{R}, f(x) = x^2$ is:
AOne-one but not onto, since some images are missed in $\mathbb{R}$
BNeither one-one nor onto, since $f(-1) = f(1)$ and negatives missed
COnto but not one-one, since every real is achieved here always
DBijective, since every real has a preimage and is unique always
Answer & Solution
Correct answer: B. Neither one-one nor onto, since $f(-1) = f(1)$ and negatives missed
$f(-1) = f(1) = 1$ so not one-one. Negatives never achieved so not onto.
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