JEE Main 2020MathematicsVector AlgebraMediumMCQ

JEE Main 2020 — Vector Algebra Question with Solution

JEE Main 2020 (07 Jan Shift 2)

Question

Let a→,b→ and c→, be three unit vectors such that a→+b→+c→=0→. If λ=a→⋅b→+b→⋅c→+c→⋅a→ and d→=a→×b→+b→×c→+c→×a→, then the order pair, λ,d→, is equal to.

Choose an option

Show full solutionCorrect option: D
Correct answer
D-32,3a→×b→

Step-by-step explanation

a→+b→+c→2=0
3+2a→·b→+b→·c→+c→·a→=0
a→·b→+b→·c→+c→·a→=-32⇒λ=-32
d→=a→×b→+b→×-a→-b→+-a→-b→×a→
=a→×b→+a→×b→+a→×b→
d→=3a→×b→.

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About this question

This is a previous-year question from JEE Main 2020, covering the Vector Algebra chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.