# NCERT Solutions for Class 10 Maths Chapter 8 Exercise 8.4

Download NCERT Solutions for Class 10 Maths Chapter 8 Exercise 8.4 Introduction to trigo in English Medium and Hindi Medium PDF form with extra questions based on trigonometric identities with answers. NCERT Solutions for class 10 all subjects and maths Hindi medium are also given to download without any login & password. Download Exercise 8.1 or  Exercise 8.2 or Exercise 8.3 also here or continue to use it online.

## NCERT Solutions for Class 10 Maths Chapter 8 Exercise 8.4

If you need solutions in Hindi, Click for Hindi Medium solutions of 10 Maths Exercise 8.4

Exercise 8.1

Exercise 8.2

Exercise 8.3

10 Maths Main Page

### Class 10 Maths Exercise 8.4 Solutions in Hindi Medium

Exercise 8.1

Exercise 8.2

Exercise 8.3

10 Maths Main Page

To get the solutions in English, Click for English Medium solutions.

##### Practice Questions for Exams
###### Trigonometric identities based questions

Question 1: Prove that (sec A – tan A)² (1 + sin A) = 1- sin A.

Question 2: Find the value of [sin A – sin B] / [cos A + cos B] + [cos A – cos B] / [sin A + sin B]. [Answer: 0]

Question 3: If 0⁰ < θ < 90⁰, prove that √[cosec θ – 1]/[cosec θ + 1] + √[cosec θ + 1]/[cosec θ – 1] = 2 sec θ.

Question 4: If 4 sin θ = 3, find the value of x if √[cosec² θ – cot² θ]/[sec² θ – 1] + 2cot θ = √7 / x + cos θ. [Answer: x = 4/3]

Question 5: If tan θ + sin θ = m and tan θ – sin θ = n, show that m² – n² = 4 √mn.

Question 6: If sin θ + cos θ = p and sec θ + cosec θ = q, show that q(p² – 1) = 2p.

Question 7: If a cos θ + b sin θ = m and a sin θ – b cos θ = n, prove that a² + b² = m² + n².

Question 8: If x = r sin A cos C, y = r sin A sin C and z = r cos A, prove that r² = x² + y² + z².

Question 9: Without using trigonometric tables, evaluate the following: (cos² 25⁰ + cos² 65⁰) + cosec θ .sec (90⁰ – θ) – cot θ .tan (90⁰ – θ) [Answer: 2].

Question 10: Prove that
(a) (i) cos (73⁰ + θ) = sin (17⁰ – θ)
(ii) tan (30⁰ – θ) = cot(60⁰ + θ)
(iii)cosec (53⁰ – θ) = sec (37⁰ + θ)
(b) (i) tan (55⁰ – θ) – cot (35⁰ + θ) = 0
(ii) cosec (65⁰ + θ) – sec (25⁰ – θ) = 0
(iii) sin (42⁰ + θ) – cos (48⁰ – θ) + cosec (11⁰ + θ) – sec (79⁰ – θ) = 0.