JEE Main 2017MathematicsVector AlgebraEasyMCQ

JEE Main 2017 — Vector Algebra Question with Solution

JEE Main 2017 (09 Apr Online)

Question

If the vector b→=3j^+4k^ is written as the sum of a vector b1→, parallel to a→= i^+ j^ and a vector b→2, perpendicular to a→, then b→1×b→2 is equal to :

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Show full solutionCorrect option: A
Correct answer
A6i^-6j^+92k^

Step-by-step explanation



b→1=b→ ⋅ a→a^2

=3j^+4k^⋅i^+ j^2 i^+ j^2

=3i^+ j^2×2=3i^+ j^2

b→1+b→2= b→

b→2= b→- b→1

=3j^+4k^-32i^+ j^

b→2= -32i^+32j^+4k^

b→1×b→2=i^j^k^32320-32324

⇒i^6- j^6+ k^94+94=6i^-6j^+92k^

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About this question

This is a previous-year question from JEE Main 2017, 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.