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Let a vector α i+β j be obtained by rotating the vector √3 i+ j by an angle 45° about the origin in counterclockwise direction in the first quadrant.…

JEE Main 2021 — Mathematics Vectors & 3D Geometry

2021mcqmedium

Let a vector αi^+βj^\alpha \hat{i}+\beta \hat{j}αi^+βj^​ be obtained by rotating the vector 3i^+j^\sqrt{3}\hat{i}+\hat{j}3​i^+j^​ by an angle 45∘45^{\circ}45∘ about the origin in counterclockwise direction in the first quadrant. Then the area (in sq. units) of triangle having vertices (α,β),(0,β)(\alpha ,\beta ),(0,\beta )(α,β),(0,β) and (0,0)(0,0)(0,0) is equal to

Official previous-year question

Held on 16 Mar 2021 · Verified 6 Jul 2026.

Options

  1. A

    12\frac{1}{2}21​

  2. B

    111

  3. C

    12\frac{1}{\sqrt{2}}2​1​

  4. D

    222\sqrt{2}22​

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