Ex 8.3, 4 (iv) - Chapter 8 Class 10 Introduction to Trignometry
Last updated at Dec. 16, 2024 by Teachoo
Ex 8.3
Ex 8.3, 1
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Transcript
Ex 8.3, 4 Prove the following identities, where the angles involved are acute angles for which the expressions are defined. ("1 + sec" A)/"sec A" ="sin2 A" /"1 โ cos A" "[Hint : Simplify LHS and RHS separately]" (1 + secโก๐ด)/secโกใ ๐ดใ = 1/secโกใ ๐ดใ +secโกใ ๐ดใ/secโกใ ๐ดใ = 1/secโกใ ๐ดใ +1 = cos A + 1 (๐๐๐๐ ๐จ)/(1 โ cosโก๐ด ) = (๐ โ ๐๐๐๐ ๐จ)/(1 โ cosโก๐ด ) = (12 โ ๐๐๐ 2 ๐ด)/(1 โ cosโก๐ด ) = ((1 โ ๐๐๐ ๐ด)(1+ cosโกใ๐ด)ใ)/(1 โ cosโก๐ด ) = 1 + cos A โด L.H.S = R.H.S Hence proved
