JEE Main 2020 · MathsNumerical answerNumerical valueEasyCalculation

JEE Main 2 September 2020, Shift 1, Maths Q75

Question 75 of 75 in this shift, Maths question 25 of 25.

Let

\vec{a}

\vec{b}

and

\vec{c}

be three unit vectors such that

|\vec{a}-\vec{b}|^{2}+|\vec{a}-\vec{c}|^{2}=8

. Then

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

is equal to ___________.

Official answer

2.00

NTA final key (Sep 2020).

Chapter: Vector Algebra
Topic: Dot Product
Idea tested: Algebraic Properties

Same topic in other shifts

All Dot Product questions

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7 Apr 2025, Shift 2 · Q15Let $\vec{a}$ and $\vec{b}$ be the vectors of the same magnitude such that…MediumSingle correct
8 Apr 2025, Shift 2 · Q14Let $\vec{a} = \hat{i} + 2\hat{j} + \hat{k}$ and $\vec{b} = 2\hat{i} + \hat{j} - \hat{k}$ . Let $\hat{c}$ be a unit vector in the plane of…MediumSingle correct

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 42 of the 174 JEE Main shifts held from 2017 to 2026.