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NDA 2012
Exam
NDA
Year
2012
Subject
Mathematics
Chapter
Matrices

NDA 2012 · Mathematics · Matrices

A and B are two matrices such that AB=A and BA=B then what is B^2...

A and B are two matrices such that AB=A\mathrm{AB}=\mathrm{A} and BA=B\mathrm{BA}=\mathrm{B} then what is B2\mathrm{B}^2 equal to? where I is the identity matrix

Options

  1. AB
  2. BA
  3. CI
  4. D-I

Correct answer

B. A

Step-by-step solution

AB=ABA=BABA=A.\begin{aligned} & \mathrm{AB}=\mathrm{A} \\ & \mathrm{BA}=\mathrm{B} \\ & \mathrm{ABA}=\mathrm{A} .\end{aligned}
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