Choose the correct answer
- Every scalar matrix is an identity matrix
- Every identity matrix is a scalar matrix
- Every diagonal matrix is an identity matrix
- A square matrix whose each element is is an identity matrix
Correct Answer: Option(b)
Option A: In a scalar matrix all diagonal elements should be equal but may or may not be equal to only.
Therefore Every scalar matrix is not a identity matrix.
Option B : In a identity matrix all elements in principal diagonal are equal (equal to ) which is a form of scalar matrix.
Therefore identity matrices are scalar.
Option C: In a diagonal matrix, the diagonal elements are non zero (but may not be ) and rest all are zeroes.
Hence every diagonal matrix may not be identity matrix.
Option D: In a identity matrix only diagonal elements are and the rest are zeroes.
Option D- incorrect