Q. 165.0( 1 Vote )
Mark the correct alternative in each of the following:
Let A = {x : –1 ≤ x ≤ 1} and f : A → A such that f(x) = x |x|, then f is
A. a bijection
B. injective but not surjective
C. surjective but not injective
D. neither injective nor surjective
Answer :
Given that A = {x: –1 ≤ x ≤ 1} and f: A → A such that f(x) = x |x|.
For x <0, f(x) <0
⇒ y = -x2
⇒ x = √-y, which is not possible for x > 0.
Hence, f is one-one and onto.
∴ the given function is bijective.
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