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Cos x + cos y formula
Ex 3.3, 11 Important
Misc 3
Misc 4 Important
Ex 3.3, 14
Ex 3.3, 15
Misc 5
Misc 7 Important
Example 16 Important
Ex 3.3, 16 Important
Ex 3.3, 17
Ex 3.3, 18 Important
Ex 3.3, 19
Ex 3.3, 20 You are here
Ex 3.3, 21 Important
Example 17 Important
Misc 6 Important
cos x + cos y formula
Last updated at May 29, 2023 by Teachoo
Ex 3.3, 20 Prove that 〖sin x − 〗sin3x /(sin2x − cos2x ) = 2 sin x Taking L.H.S. 〖sin x −〗sin3x /(sin2x − cos2x ) We solve sin x – sin 3x & sin2 x – cos2 x separately Now, sin〖𝑥 − sin3𝑥 〗/sin2〖𝑥 − cos2𝑥 〗 = 〖2 𝑐𝑜𝑠 〗〖2𝑥 〖 sin〗〖(−𝑥)〗 〗/〖−𝑐𝑜𝑠〗2𝑥 = 〖2 𝑐𝑜𝑠〗〖2𝑥 〖(− sin〗𝑥)〗/〖−𝑐𝑜𝑠〗2𝑥 = 2sin x = R.H.S. Hence L.H.S. = R.H.S. Hence proved