# NCERT Solutions for Class 10 Maths Chapter 8 Exercise 8.4

NCERT Solutions for class 10 Maths Chapter 8 Exercise 8.4 Introduction to Trigonometry in Hindi Medium and English Medium PDF form to free download updated for new academic year 2020-21 for all students.

Download Offline apps based on these solutions or View in Video Format for all board whoever using NCERT Books 2020-2021 for their CBSE based exams. Download (Exercise 8.4) in PDF form or CBSE Offline Apps or use the solutions and proof given below as online.## NCERT Solutions for class 10 Maths Chapter 8 Exercise 8.4

Class: | 10 |

Subject: | Maths – गणित |

Chapter 8: | Exercise 8.4 |

### 10 Maths Chapter 8 Exercise 8.4 Solutions

NCERT Solutions for class 10 Maths Chapter 8 Exercise 8.4 Introduction to Trigonometry in English Medium as well as Hindi Medium are given below free to use online and liberty to download for offline use. NCERT Solutions Offline Apps with complete description of each questions along with reason of each step are given to free use. All questions are done by the qualified and expert teachers to provide the best for the students. Visit to Class 10 Maths Chapter 8 main page for other exercises whether download or online study.

### Class 10 Maths Exercise 8.4 Solutions

#### Important Questions for Proof

1. If A, B, C are the angles of triangle ABC then prove that cosec2[(B + C)/2] – tan2(A/2) = 1.

2. Prove the following: 2 (sin^6 A + cos^6 A) – 3 (sin^4 A + cos^4 A) + 1 = 0

3. Prove that: (1 + cot A + tan A) (sin A – cos A) = sin A tan A – cot A cos A

4. If sin θ + cos θ = m and sec θ + cosec θ = n then show that n(m² – 1) = 2m.

##### Questions from Board Papers

1. If time bound and continuity are two measurable quantities respectively equal to A & B. If sin (A – B) = 1/2, cos(A + B) = 1/2, where 0° < A + B ≤ 90° find the values of A and B. [Answer: A = 45, B = 15] 2. If x = sin²θ, y = cos²θ, where x & y represents honesty and hard work. (a) What will be the result after joining honesty & hard work? (b) Which mathematical concept has been used here? [Answer: (a) 1, (b) Trigonometry]

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