JEE Main 2019PhysicsMathematics in PhysicsEasyMCQ

JEE Main 2019 — Mathematics in Physics Question with Solution

JEE Main 2019 (08 Apr Shift 2)

Question

Let A1→=3, A2→=5  and A1→+A2→=5. The value of 2A1→+3A2→∙3A1→-2A2→ is:

Choose an option

Show full solutionCorrect option: B
Correct answer
B-118.5

Step-by-step explanation

A→1+A→2=5
A→1+A→22=25
A→12+A→22+2A→1A→2=25
9+25+2A→1∙A→2=25
A→1.A→2=-92
Now, 2A→1+3A→2∙3A→1-2A→2=6A→12-4A→1A→2+9A→1A→2-6A→22
=6.A→12+5A→1A→2-6A→22
=6×9+5-92-6×25
=54-452-150
= -118.5

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About this question

This is a previous-year question from JEE Main 2019, covering the Mathematics in Physics chapter of Physics. 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.