If sin A + sin 2 A = 1, then the value of the expression (cos 2 A + cos 4 A) is
(A) 1 (B) 1/2 (C) 2 (D) 3
Last updated at Dec. 16, 2024 by Teachoo
Question 12 If sin A + sin2 A = 1, then the value of the expression (cos2 A + cos4 A) is (A) 1 (B) 1/2 (C) 2 (D) 3 Given sin A + sin2 A = 1 sin A = 1 − sin2 A sin A = cos2 A Now, cos2 A + cos4 A = cos2 A + (cos2 A) 2 Putting cos2 A = sin A = sin A + sin2 A Given sin A + sin2 A = 1 = 1 So, the correct answer is (A)
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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo