

NCERT Solutions for Class 12 Maths Chapter 3 Miscellaneous Exercise
Solve The Following Questions NCERT Solutions for Class 12 Maths Chapter 3 Exercise 3.3 Matrices
Question 1. Find the transpose of each of the following matrices: (i)
(ii)
(iii)
Solution :
(i) Let A =
Transpose of A = A’ or A
T
= [ 5 1/2 -1]
(ii)
Transpose of A = A’ or A
T
=
(iii)
Transpose of A = A’ or A
T
=
NCERT Solutions for Class 12 Maths Chapter 3 Exercise 3.1
Question 2. If
then verify that:
(i)
(A + B)' = A' + B'
(ii)
(A - B)' = A' - B'
Solution :
NCERT Solutions for Class 12 Maths Chapter 3 Exercise 3.2
Question 3. If
then verify that:
(i)
(A + B)' = A' + B'
(ii)
(A - B)' = A' - B'
Solution :
NCERT Solutions for Class 12 Maths Chapter 3 Exercise 3.4
Question 4. If
then find (A + 2B)’.
Solution :
(ii)
Solution :
| NCERT Solutions for Class 12 Maths Chapter 2 Exercise 2.1 | NCERT Solutions for Class 12 Maths Chapter 2 Exercise 2.2 |
| NCERT Solutions for Class 12 Maths Chapter 2 Miscellaneous Exercise | |
then verify that A’A = I.
(ii) If A =
then verify that A’A = I.
Solution :
Question
7. (i) Show that the matrix A =
is a symmetric matrix.
(ii) Show that the matrix A =
is a skew symmetric matrix.
Solution :
(i) Given: A =
Changing rows of matrix A as the columns of new matrix A’ =
= A
∴ A’ = A
Therefore, by definitions of symmetric matrix, A is a symmetric matrix.
(ii) Given: A =
A’ =
=
-
= - A
∴ A’ = - A
Therefore, by definition matrix A is a skew-symmetric matrix
Question
8. For a matrix A =
verify that:
(i) (A + A’) is a symmetric matrix.
(ii) (A – A’) is a skew symmetric matrix.
Solution :
Question
9. Find 1/2 (A + A’) and 1/2(A – A’) when A =
Solution :
Question
10. Express the following matrices as the sum of a symmetric and skew symmetric matrix:
(i)
(ii)
(iii)
(iv)
Solution :
(iii)
(iv)
Choose the correct answer in Exercises 11 and 12.
Question 11. If A and B are symmetric matrices of same order, AB – BA is a: (A) Skew-symmetric matrix (B) Symmetric matrix (C) Zero matrix (D) Identity matrix Solution : Given: A and B are symmetric matrices ∴ A = A’ and B = B’ Now, (AB – BA)’ = (AB)’ – (BA)’ ∴ (AB – BA)’ = B’A’ – A’B’ [Reversal law] ∴ (AB – BA)’ = BA – AB [From eq. (i)] ∴ (AB – BA)’ = – (AB – BA) ∴ (AB – BA) is a skew matrix. Therefore, option (A) is correct. Question 12. If A =
, then A + A’ = I, if the value of
α is:
(A) π/6
(B) π/3
(C)
π
(D) 3
π/2
Solution :
Therefore, option (B) is correct.
