Last updated at June 29, 2018 by Teachoo

Transcript

Ex 8.3, 6 If A, B and C are interior angles of a triangle ABC, then show that sin ((B + C)/2)= cos ๐ด/2 In ฮ ABC Sum of angles of a triangle = 180 ยฐ A + B + C = 180ยฐ B + C = 180ยฐ โ A Multiplying both sides by 1/2 (๐ต + ๐ถ)/2 " = " (180ยฐ โ ๐ด)/2 (๐ต + ๐ถ)/2 " = " (180ยฐ)/2 โ ๐ด/2 (๐ต + ๐ถ)/2 " = " 90ยฐ โ ๐ด/2 Taking L.H.S sin ((๐ต + ๐ถ)/2) = sin ("90ยฐ โ " ( ๐ด)/2) = ๐๐๐ ๐ด/2 = R.H.S Hence proved

Chapter 8 Class 10 Introduction to Trignometry

Example 2
Important

Example 6 Important

Example 7 Important

Example 11 Important

Example 15 Important

Ex 8.1, 5 Important

Ex 8.1, 10 Important

Ex 8.1, 9 Important

Ex 8.3, 5 Important

Ex 8.1, 11 Important

Ex 8.3, 6 Important You are here

Ex 8.3, 7 Important

Ex 8.4, 1 Important

Ex 8.4, 2 Important

Ex 8.4, 5 Important

Class 10

Important Questions for Exam - Class 10

- Chapter 1 Class 10 Real Numbers
- Chapter 2 Class 10 Polynomials
- Chapter 3 Class 10 Pair of Linear Equations in Two Variables
- Chapter 4 Class 10 Quadratic Equations
- Chapter 5 Class 10 Arithmetic Progressions
- Chapter 6 Class 10 Triangles
- Chapter 7 Class 10 Coordinate Geometry
- Chapter 8 Class 10 Introduction to Trignometry
- Chapter 9 Class 10 Some Applications of Trignometry
- Chapter 10 Class 10 Circles
- Chapter 11 Class 10 Constructions
- Chapter 12 Class 10 Areas related to Circles
- Chapter 13 Class 10 Surface Areas and Volumes
- Chapter 14 Class 10 Statistics
- Chapter 15 Class 10 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.