Ex 8.4, 5 - Chapter 8 Class 10 Introduction to Trignometry - Part 3

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Ex 8.4, 5 - Chapter 8 Class 10 Introduction to Trignometry - Part 4

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  1. Chapter 8 Class 10 Introduction to Trignometry (Term 1)
  2. Serial order wise

Transcript

Ex 8.4, 5 Prove the following identities, where the angles involved are acute angles for which the expressions are defined. (ii) "cos A" /"1 + sin A" +"1 + sin A" /"cos A" =2 sec A Taking L.H.S (cos )/(1 + sin )+(1 + sin )/(cos ) = (cos (cos ) + (1 + sin )(1 + sin ) )/((1 + sin )(cos )) = ( 2 + (1 + sin )2)/((1 + sin )(cos )) = ( 2 + 1^2 + 2 + 2 sin )/((1 + sin )(cos )) = (( 2 + 2 ) + 1 + 2 sin )/((1 + sin )(cos ) ) = (1 + 1 + 2 sin )/((1 + sin )(cos ) ) = (2 + 2 sin )/((1 + sin )(cos ) ) = (2(1+ sin ))/((1 + sin )(cos ) ) = 2/(cos ) = 2 1/cos = 2 sec A = R.H.S L.H.S = R.H.S Hence proved

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.