

There is some mistake in this Video. Please check images above.
Finding Value of trignometric functions, given angle
Finding Value of trignometric functions, given angle
Last updated at Dec. 13, 2024 by Teachoo
There is some mistake in this Video. Please check images above.
Transcript
Ex 3.3, 2 Prove that 2sin2 π/6 + cosec2 7π/6 cos2 π/3 = 3/2 Solving L.H.S 2sin2 π/6 + cosec2 7π/6 cos2 π/3 Putting π = 180° = 2 sin2 180/6 + cosec2 (7 ×180)/6 cos2 180/3 = 2sin2 30° + cosec2 210° cos2 60° = 2(sin 30°)2 + (cosec 210°)2 (cos 60°)2 For cosec 210° , Lets first calculate sin 210° sin 210° = sin (180° + 30°) = −sin 30° = (−1)/2 So, cosec 210° = 1/sin〖210°〗 = 1/((−1)/2) = 2/(−1 ) = –2 Putting values in equation 2(sin 30°)2 + (cosec 210°)2 (cos 60°)2 = 2 (1/2)^2 + (–2)2 × (1/2)^2 = 2 × 1/4 + 4 × 1/4 = 𝟏/𝟐 + 1 = 1/2 + 1 = 3/2 = R.H.S Hence proved