NCERT Exemplar Solutions
Class 12 - Mathematics - Chapter 3: MatricesFill in the Blanks
Class 12 - Mathematics - Chapter 3: Matrices
Question. 68
_____ matrix is both symmetric and skew symmetric matrix.
Answer:
Null matrix
Question. 69
Sum of two skew symmetric matrices is always _____ matrix.
Answer:
Skew symmetric matrix
Question. 70
The negative of a matrix is obtained by multiplying it by _____.
Answer:
-1
Question. 71
The product of any matrix by the scalar _____ is the null matrix.
Answer:
0
Question. 72
A matrix which is not a square matrix is called a _____ matrix.
Answer:
Rectangular matrix
Question. 73
Matrix multiplication is _____ over addition.
Answer:
Distributive
Question. 74
If A is a symmetric matrix, then A\(^3\) is a _____ matrix.
Answer:
Symmetric matrix
Question. 75
If A is a skew symmetric matrix, then A\(^2\) is a ____.
Answer:
Symmetric matrix
Question. 77
If A is skew symmetric, then kA is a _____ (k is any scalar).
Answer:
Skew symmetric matrix
Question. 79
If A is symmetric matrix, then B'AB is ____.
Answer:
Symmetric matrix
Question. 80
If A and B are symmetric matrices of same order, then AB is symmetric if and only if ____.
Answer:
AB = BA
Question. 81
In applying one or more row operations while finding A\(^{-1}\) by elementary row operations, we obtain all zeros in one or more, then A\(^{-1}\) ____.
Answer:
does not exist
Question. 76_i
If A and B are square matrices of the same order, then (i) (AB)' = ____.
Answer:
B' A'
Question. 76_ii
(ii) (kA)' = ____ (k is any scalar)
Answer:
kA
Question. 76_iii
(iii) [k(A − B)]' = ____.
Answer:
k(A − B)
Question. 78_i
If A and B are symmetric matrices, then (i) AB − BA is a ____.
Answer:
Skew symmetric matrix
Question. 78_ii
(ii) BA − 2AB is a ____.
Answer:
neither symmetric nor skew symmetric matrix