Last updated at May 29, 2018 by Teachoo

Transcript

Ex3.3, 18 Prove that 〖sin x − 〗siny /(𝑐𝑜𝑠x + 𝑐𝑜𝑠y ) = tan (x − y)/2 Solving L.H.S 〖sin x − 〗siny /(𝑐𝑜𝑠x + 𝑐𝑜𝑠y ) We Know that sin x – sin y = 2 cos ( (𝑥 + 𝑦 )/2) sin ( (𝑥 − 𝑦 )/2) & cos x + cos y = 2 cos ( (𝑥 + 𝑦 )/2) cos ( (𝑥 − 𝑦 )/2) 〖sin x − 〗siny /(𝑐𝑜𝑠x + 𝑐𝑜𝑠y ) = 〖2 𝑐𝑜𝑠 ((𝑥 + 𝑦)/2)〗〖 𝑠𝑖𝑛〖 ((𝑥 − 𝑦)/2)〗 〗/(2 𝑐𝑜𝑠〖 ((𝑥 + 𝑦)/2)〗 𝑐𝑜𝑠〖 ((𝑥 − 𝑦)/2)〗 ) = 𝑠𝑖𝑛〖" " ((𝑥 − 𝑦 )/2)〗/(𝑐𝑜𝑠〖 ((𝑥 − 𝑦)/2)〗 ) = tan (𝑥 − 𝑦 )/2 = R.H.S Hence L.H.S. = R.H.S. Hence proved

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Ex 3.3, 18 Important You are here

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Chapter 3 Class 11 Trigonometric Functions

Serial order wise

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.