Square matrix and diagonal matrix

The matrix A=[004040400] is a (a) square matrix (b) diagonal matrix (c) unit matrix (d) none of these

Which of the following is a triangular matrix? (A) a scalar matrix (B) a lower triangular matrix (C) an upper triangular matrix (D) a diagonal matrix

The inverse of a diagonal matrix is a. a diagonal matrix b. a skew symmetric matrix c. a symmetric matrix d. none of these

Consider the following statements : 1. every zero matrix is a square matrix. 2. A matrix has a numerical value. 3. A unit matrix is a diagonal matrix. Which of the above statements is/are correct ?

Consider the following statements. I. Every zero matrix is a square matrix II. A matrix has a numerical value III. A unit matrix is a diagonal matrix Which of the above statement is/are correct ?

Inverse OF square matrix || Orthogonal matrix

Give an example of a row matrix which is also a column matrix a diagonal matrix which is not scalar (iii) a triangular matrix.

If A is a skew-symmetric matrix and n is odd positive integer,then A^(n) is a skew-symmetric matrix a symmetric matrix a diagonal matrix none of these

Which of the following is/are incorrect? (i).Adjoint of symmetric matrix is symmetric (ii).Adjoint of unit matrix is a unit matrix (iii). A(adjA)=(adjA)A=!|A|I (iv). Adjoint of a diagonal matrix is a diagonal matrix

Which of the following is/are incorrect? (i) adjoint of a symmetric matrix is symmetric (ii) adjoint of a unit matrix is a unit matrix (iii) A (adj A)=(adj A)A=absAI (iv) adjoint of a diagonal matrix is a diagonal matrix