Last updated at June 29, 2018 by Teachoo

Transcript

Ex 8.3, 6 If A, B and C are interior angles of a triangle ABC, then show that sin ((B + C)/2)= cos ๐ด/2 In ฮ ABC Sum of angles of a triangle = 180 ยฐ A + B + C = 180ยฐ B + C = 180ยฐ โ A Multiplying both sides by 1/2 (๐ต + ๐ถ)/2 " = " (180ยฐ โ ๐ด)/2 (๐ต + ๐ถ)/2 " = " (180ยฐ)/2 โ ๐ด/2 (๐ต + ๐ถ)/2 " = " 90ยฐ โ ๐ด/2 Taking L.H.S sin ((๐ต + ๐ถ)/2) = sin ("90ยฐ โ " ( ๐ด)/2) = ๐๐๐ ๐ด/2 = 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 9 years. He provides courses for Maths and Science at Teachoo.