JEE Main 2022 · MathsNumerical answerNumerical valueHardMulti-step

JEE Main 28 June 2022, Shift 2, Maths Q27

Question 27 of 90 in this shift, Maths question 27 of 30, Section B.

Let

A=\begin{pmatrix}1+i & 1\\ -i & 0\end{pmatrix}

where

i=\sqrt{-1}

. Then, the number of elements in the set

\{n \in \{1, 2, \ldots, 100\} : A^n = A\}

is __________.

Official answer

NTA final key.

Chapter: Matrices
Topic: Matrix Multiplication
Idea tested: Periodic Matrices

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.