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Ex 8.4
Ex 8.4, 2 Important
Ex 8.4, 3 (i) Important
Ex 8.4, 3 (ii)
Ex 8.4, 4 (i) [MCQ]
Ex 8.4, 4 (ii) [MCQ] Important
Ex 8.4, 4 (iii) [MCQ] Important
Ex 8.4, 4 (iv) [MCQ]
Ex 8.4, 5 (i) Important
Ex 8.4, 5 (ii) You are here
Ex 8.4, 5 (iii) Important
Ex 8.4, 5 (iv) Important
Ex 8.4, 5 (v) Important
Ex 8.4, 5 (vi)
Ex 8.4, 5 (vii) Important
Ex 8.4, 5 (viii)
Ex 8.4, 5 (ix) Important
Ex 8.4, 5 (x)
Last updated at March 29, 2023 by Teachoo
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