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Last updated at Dec. 8, 2016 by Teachoo

Transcript

Ex 3.3, 1 Prove that sin2 /6 + cos2 /3 tan2 /4 = 1/2 Taking L.H.S sin2 /6 + cos2 /3 - tan2 /4 Putting = 180 = sin2 180/6 + cos2 180/3 tan2 180/6 = sin2 30 + cos2 60 tan2 45 = (sin 30 )2 + ( sin 60 )2 (tan 45 )2 Putting sin 30 = 1/2 sin 60 = 1/2 tan 45 = 1 = (1/2)^2 + (1/2)^2 12 = 1/4+ 1/4 1 = (1 + 1 4 )/4 = (2 4 )/4 = ( 2)/4 = ( 1)/2 = R.H.S. Hence proved

Finding Value of trignometric functions, given angle

Negative Angle Identities

Value of sin, cos, tan repeats after 2π

Shifting angle by π/2, π, 3π/2 , 2π

Example 8

Ex 3.2, 9 Important

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 You are here

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.