JEE Main 2021MathematicsMatricesEasyMCQ

JEE Main 2021 — Matrices Question with Solution

JEE Main 2021 (25 Feb Shift 2)

Question

If for the matrix, A=1-ααβ, AAT=I2, then the value of α4+β4 is :

Choose an option

Show full solutionCorrect option: B
Correct answer
B1

Step-by-step explanation

A=1-ααβ  AAT=I2

⇒1-ααβ1α-αβ=1001

⇒1+α2α-αβα-αβα2+β2=1001

⇒1+α2=1 & α2+β2=1

⇒α2=0 & β2=1

∴ α4=0 & β4=1

∴ α4+β4=1

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About this question

This is a previous-year question from JEE Main 2021, 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.