Last updated at May 29, 2018 by Teachoo

Transcript

Ex 8.4, 2 Write all the other trigonometric ratios of A in terms of sec A. cos A We know that cos A = / tan A We know that 1 + tan2 A = sec2 A tan2 A = sec2 A 1 tan A = ( 2 1) Here, A is acute (i.e. less than 90 ) & tan A is positive when A is acute tan A = ( 2 1) cot cot A = /( ) Putting value of tan A found above cot A = 1/( (sec^2 1 ) ) cosec A We know that 1 + cot2 A = cosec2 A cosec2 A = 1 + cot2 A cosec2 A = 1 + (1/( (sec^2 1 ) ))^2 cosec2 A = 1 + (1/( 2 1)) cosec2 A = ((1 ( 2 1) + 1)/( 2 1)) cosec2 A = (( 2 1 + 1)/( 2 1)) cosec2 A = ( 2 )/( 2 1) cosec A = (( 2 )/( 2 1)) cosec A = sec / ( 2 1 ) Here, A is acute (i.e. less than 90 ) & cosec A is positive when A is acute cosec A = sec / ( 2 1 ) sin A We know that sin A = /( ) sin A = 1/((sec / (sec^2 1 )) ) sin A = ( 2 1)/sec

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

Ex 8.3, 7 Important

Ex 8.4, 1 Important

Ex 8.4, 2 Important You are here

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.