

NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.1 Determinants is prepared by academic team of Physics Wallah. We have prepared NCERT Solutions for all exercise of chapter 4. Given below is step by step solutions of all questions given in NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.1 Determinants.
NCERT Solutions for Class 12 Maths Chapter 4 Miscellaneous Exercise
NCERT Solutions Class 12 Maths Chapter 4 PDF Download Link
Solve The Following Questions of NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.1 Determinants
Evaluate the following determinants in Exercise 1 and 2. Question 1.
Solution :
= 2(-1) - 4(-5) = -2 + 20 = 18
NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.2
Question 2. (i)
(ii)
Solution :
(i)
= (cosθ)(cosθ) - (-sinθ) (sinθ)= cos
2
θ + sin
2
θ= 1
(ii)
= (
x
2
−
x
+ 1)(
x
+ 1) − (
x
− 1)(
x
+ 1)
=
x
3
−
x
2
+
x
+
x
2
−
x
+ 1 − (
x
2
− 1)
=
x
3
+ 1 −
x
2
+ 1
=
x
3
−
x
2
+ 2
NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.3
Question
3. If A =
then show that |2A| = 4|A|
then 2A =
2 x
Hence, proved.
NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.4
Question 4. If A =
then show that 3|A| = 27|A|
Solution :
Given: A =
then 3A =
3
It can be observed that in the first column, two entries are zero. Thus, we expand along the first column (C
1
) for easier calculation.
Hence, proved.
NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.5
Question 5. Evaluate the determinants: (i)
(ii)
(iii)
(iv)
Solution :
Evaluate the determinants:
(i) Given:
It can be observed that in the second row, two entries are zero. Thus, we expand along the second row for easier calculation.
=
(ii) Given:
By expanding along the first row, we have:
=
(iii) Given:
Expanding along first row,
=
= 0 + 6 – 6 = 0
(iv) Given:
Expanding along first row,
=
= -10 + 15 = 5
NCERT Solutions for Class 12 Maths Chapter 4 Exercise 4.6
Question 6. If A =
find |A|
Solution :
Given: A =
Expanding along first row,
=
(ii)
Solution :
(i) Given:
⇒ 2 x 1 - 5 x 4 = 2x * x - 6 x 4
⇒ 2 - 20 = 2x
2
- 24
⇒ 2x
2
= 6
⇒ x
2
= 3
⇒ x = ± √3
(ii)
⇒ 2 x 5 - 4 x 3 = x * 5 - 2x - 3
⇒10 - 12 = 5x - 6x
⇒ - 2 = -x
⇒ x = 2
| 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 x is equal to:
(A) 6
(B) ± 6
(C) - 6
(D) 0
Solution :
Given:
⇒x * x - 18 x 2 = 6 x 6 - 18 x 2
⇒x
2
- 36 = 36 - 36
⇒x
2
- 36 = 0
⇒x = ± 6
Therefore, option (B) is correct.
