Last updated at May 29, 2018 by Teachoo

Transcript

Example 17 Prove that sin 5x 2sin 3x + sin x / 5x x = tan x Taking L.H.S. sin 5x + sin x 2sin 3x / 5x x = (sin 5x + sin x ) 2sin 3x / 5x x Solving numerator and denominator separately Taking R.H.S sin 5x + sin x 2sin 3x / 5x x Putting values = (2 sin 3 cos 2 2 sin 3 )/( 2 sin 3 sin 2 ) = (2 sin 3 (cos 2 1) )/( 2 sin 3 sin 2 ) = ( (cos 2 1) )/( sin 2 ) = ( (cos 2 1) )/sin 2 = ( 1 cos 2 )/sin 2 = (1 (1 2 sin2 ) )/(2 cos sin ) = (0 + 2 sin2 )/(2 cos sin ) = (2 sin2 )/(2 cos sin ) = sin /cos = tan x = R.H.S. Hence L.H.S. = R.H.S. Hence proved

Chapter 3 Class 11 Trigonometric Functions

Concept wise

- Radian measure - Conversion
- Arc length
- Finding Value of trignometric functions, given other functions
- Finding Value of trignometric functions, given angle
- (x + y) formula
- 2x 3x formula - Proving
- 2x 3x formula - Finding value
- cos x + cos y formula
- 2 sin x sin y formula
- Finding Principal solutions
- Finding General Solutions
- Sine and Cosine Formula

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.