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CUET · MATHS · PYQ PAPER 2023

Let \(f:[-2,2] \rightarrow[-2,2]\) be a function defined by \(f(x)=x|x|\), then \(f\) is:

  1. A One-one but not onto
  2. B Onto but not one-one
  3. C Neither one-one nor onto
  4. D Bijective
Verified Solution

Answer & Solution

Correct Answer

(D) Bijective

Step-by-step Solution

Detailed explanation

Let \(f(x_1) = f(x_2)\). Then \(x_1|x_1| = x_2|x_2|\). Since \(x|x|\) has the same sign as \(x\), \(x_1\) and \(x_2\) must have the same sign. If \(x_1, x_2 \ge 0\), \(x_1^2 = x_2^2 \implies x_1 = x_2\). If \(x_1, x_2 \(f\) is one-one. Let \(y \in [-2,2]\) (codomain). If…