Let a = i + 2j + 4k, b = i + λj + 4k and c = 2i + 4j + (λ^2 - 1)k be coplanar vectors. Then, the non-zero vector a × c is

Let a = i + 2j + 4k, b = i + λj + 4k and c = 2i + 4j + (λ^2… — JEE Main 2019 Mathematics PYQ

JEE Main 2019 · 11 Jan · Shift I

Let

\vec{a} = \hat{i} + 2\hat{j} + 4\hat{k}

\vec{b} = \hat{i} + \lambda\hat{j} + 4\hat{k}

and

\vec{c} = 2\hat{i} + 4\hat{j} + (\lambda^2 - 1)\hat{k}

be coplanar vectors. Then, the non-zero vector

\vec{a} \times \vec{c}

Show answer

Correct option: A

[JEE Main 2019 · 11 Jan · Shift I]

Practise Vector Algebra the way it is asked

A timed set of real JEE Main Vector Algebra questions, graded as the exam grades. No sign-up.