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NDA 2012
Exam
NDA
Year
2012
Subject
Mathematics
Chapter
Matrices

NDA 2012 · Mathematics · Matrices

A square matrix [a_ i j ] such that a_ i j =0 for i ≠ j and a_ i j...

A square matrix [aij]\left[a_{i j}\right] such that aij=0a_{i j}=0 for i≠jandaij=ki \neq j and a_{i j}=k where kk is a constant for i=ji=j is called :

Options

  1. Adiagonal matrix, but not scalar matrix
  2. Bscalar matrix
  3. Cunit matrix
  4. DNone of the above

Correct answer

B. scalar matrix

Step-by-step solution

In a scalar matrix, a_{i j}=\left\{0 for  i≠jk for  i=j\begin{array}{lll}0 & \text{\text{ for } } \quad i \neq j \\ k &\text{\text{ for } } \quad i=j\end{array}\right. Example \left[400040004\begin{array}{lll}4 & 0 & 0 \\ 0 & 4 & 0 \\ 0 & 0 & 4\end{array}$$\right]
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