JEE Main 2021 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 24 February 2021, Shift 1, Maths Q89

Question 89 of 90 in this shift, Maths question 29 of 30, Section B.

Let three vectors

\vec{a}, \vec{b}

and

\vec{c}

be such that

\vec{c}

is coplanar with

\vec{a}

and

\vec{b}

\vec{a} \cdot \vec{c} = 7

and

\vec{b}

is perpendicular to

\vec{c}

, where

\vec{a} = -\hat{i} + \hat{j} + \hat{k}

and

\vec{b} = 2\hat{i} + \hat{k}

, then the value of

2|\vec{a} + \vec{b} + \vec{c}|^2

is ___________.

Official answer

NTA final key.

Chapter: Vector Algebra
Topic: Triple Products
Idea tested: Constructing Orthogonal Coplanar Vectors

Same topic in other shifts

All Triple Products questions

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.