Last updated at May 29, 2018 by Teachoo

Transcript

Ex 8.1, 5 Given sec θ =13/12, calculate all other trigonometric ratios. Finding cos θ cos θ = 1/secθ cos θ = 1/(13/12) cos θ = 12/13 (𝑠𝑖𝑑𝑒 𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡 𝑡𝑜 ∠𝜃)/𝐻𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒 = 12/13 𝐴𝐵/𝐴𝐶=12/13 Let AB = 12x & AC = 13x Using Pythagoras theorem to find BC (Hypotenuse)2 = (Height)2 + (Base)2 AC2 = AB2 + BC2 (13x)2 = (12x)2 + (BC)2 (BC)2 = (13x)2 - (12x)2 (BC)2 = (13x)2 - (12x)2 (BC) 2 = 169x2 – 144x2 (BC) 2 = 25x2 BC = √(25𝑥^2 ) BC = √(5^2 𝑥^2 ) BC = 5x sin θ = (𝑠𝑖𝑑𝑒 𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 ∠𝜃)/𝐻𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒 = 𝐵𝐶/𝐴𝐶 = 5𝑥/13𝑥 = 5/13 cos θ = 12/13 tan θ = (𝑠𝑖𝑑𝑒 𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 ∠𝜃)/(𝑠𝑖𝑑𝑒 𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡 𝑡𝑜 ∠𝜃) tan θ = 𝐵𝐶/𝐴𝐵 tan θ = 5𝑥/12𝑥 tan θ = 5/12

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 You are here

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

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 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.