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Last updated at Feb. 12, 2020 by Teachoo

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Ex 3.2,9 Find the value of the trigonometric function sin (β11"Ο" /3) sin ((β11 π)/3) = βsin ((11 π)/3) = βsin ("3 " 2/3 " Ο" ) = βsin ("4Ο β " 1/3 " Ο" ) = βsin ((β1)/3 " Ο" ) Values of sin x repeats after an interval of 2Ο , Hence ignoring 4Ο i.e. 2 Γ (2Ο) Rough So, 11/3 = 3 2/3 = 3 + 2/3 or 4 β 1/3 We take 4 β 1/3 as it is even = β ("βsin " (1/3 " Ο" )) = sin (1/3 " Ο" ) = sin 60Β° = βπ/π ( As sin(βx) = βsin x )

Finding Value of trignometric functions, given angle

Negative Angle Identities

Value of sin, cos, tan repeats after 2Ο

Shifting angle by Ο/2, Ο, 3Ο/2 , 2Ο

Example 8

Ex 3.2, 9 Important You are here

Ex 3.2, 8 Important

Ex 3.2, 10 Important

Example 9 Important

Ex 3.2, 6

Ex 3.2, 7 Important

Example 10

Ex 3.3, 1

Ex 3.3, 2 Important

Ex 3.3, 3 Important

Ex 3.3, 4

Ex 3.3, 8 Important

Ex 3.3, 9 Important

Find values of sin 18, cos 18, cos 36, sin 36, sin 54, cos 54 Important

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.