The least number of zero elements in a diagonal matrix of order 4 is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 12
In a diagonal matrix every element off the main diagonal is zero; the diagonal elements may or may not be zero.
A square matrix of order 4 has
\(4 \times 4 = 16\) elements
Of these, 4 lie on the main diagonal, so the number of elements off the diagonal is
\(16 - 4 = 12\)
These 12 elements are always zero, and the diagonal elements can all be non-zero. So the least number of zeros is 12.