JEE Main 2013MathematicsMatricesMediumMCQ

JEE Main 2013 — Matrices Question with Solution

JEE Main 2013 (07 Apr)

Question

If P=1α3133244 is the adjoint of a 3×3 matrix A and A=4, then α is equal to

Choose an option

Show full solutionCorrect option: D
Correct answer
D11

Step-by-step explanation

Given P=adjA

⇒P=adjA=A2  ∵  adjA=An-1 where n=3

Now, P=1α3133244=1×12−12−α×4−6+3×4−6=2α-6

⇒2α-6=16

⇒ α = 11

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About this question

This is a previous-year question from JEE Main 2013, covering the Matrices 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.