NCERT Solutions For Class 10 Maths Chapter 8 Introduction to Trigonometry Ex 8.4
Here, Below you all know about NCERT Solutions for Class 10 Maths Chapter 8 Introduction to Trigonometry Ex 8.4 Question Answer. I know many of you confuse about finding Chapter 8 Introduction to Trigonometry Ex 8.4 Of Class 10 NCERT Solutions. So, Read the full post below and get your solutions.
Textbook | NCERT |
Board | CBSE |
Category | NCERT Solutions |
Class | Class 10 |
Subject | Maths |
Chapter | Chapter 8 |
Exercise | Class 10 Maths Chapter 8 Introduction to Trigonometry Exercise 8.4 |
Number of Questions Solved | 5 |

NCERT Solutions for Class 10 Maths Chapter 8 Introduction to Trigonometry Ex 8.4
NCERT TEXTBOOK EXERCISES
Question 1. Express the trigonometric ratios sin A, sec A and tan A in terms of cot A.
Solution:
From trigonometric identity, cosec² A – cot² A = 1, we get

Question 2. Write all the other trigonometric ratios of ∠A in terms of sec A.
Solution:
Since sin² A + cos² A = 1, therefore

Question 3. Evaluate:
(I)

(ii) sin 25° cos 65° + cos 25° sin 65°
Solution:

(ii) sin 25° cos 65° + cos 25° sin 65° = sin 25° cos (90° – 25°) + cos 25° sin (90° – 25°)
= sin 25° sin 25° + cos 25° cos 25°
= sin² 25° + cos² 25° = 1
Question 4. Choose the correct option. Justify your choice.
(i) 9 sec² A – 9 tan² A =
(A) 1
(B) 9
(C) 8
(D) 0
(ii) (1 + tan θ + sec θ) (1 + cot θ – cosec θ ) =
(A) 0
(B) 1
(C) 2
(D) -1
(iii) (sec A + tan A) (1 – sin A) =
(A) sec A
(B) sin A
(C) cosec A
(D) cos A
(iv) 1+tan2A1+cot2A
(A) sec² A
(B) -1
(C) cot² A
(D) tan² A
Solution:
(i) 9 sec² A – 9 tan² A = 9(sec² A – tan² A) = 9 x 1 = 9
Correct option is (B)

Question 5. Prove the following identities, where the angles involved are acute angles for which the expressions are defined.

Solution:



NCERT Solutions for Class 10 Maths Chapter 8 Introduction to Trigonometry Exercise 8.4 PDF
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