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Ex 8.4, 5 - Chapter 8 Class 10 Introduction to Trignometry (Term 1)
Last updated at Aug. 11, 2021 by Teachoo
Chapter 8 Class 10 Introduction to Trignometry
Concept wise
- Finding sin cos tan
- Finding sin cos when sides of a triangle are given
- Finding ratios when other ratios are given
- Finding values of expressions
- Proving
- Trignometric ratios of Specific Angles - Evaluating
- Trignometric ratios of complementry angles
- Expressing ratios in other ratios
-
Evaluating using Trignometric Identities
Transcript
Ex 8.4, 5 Prove the following identities, where the angles involved are acute angles for which the expressions are defined. (i) (cosec cot )2 = (1 " " )/(1 + cos ) Solving L.H.S (cosec cot )2 We need to make it in terms of cos & sin = (1/sin cos /sin )^2 = (("1 " cos )/sin )^2 = ((1 cos )2 )/( 2 ) = ((1 cos )2 )/(1 2 ) = ((1 cos )2 )/(12 2 ) = (1 cos )^2/((1 + cos )(1 cos )) = ((1 cos )(1 ) )/((1 + cos )(1 cos )) = (1 cos )/(1 + cos ) = RHS Hence proved
