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
NCERT Exemplar - MCQ
NCERT Exemplar - MCQ
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)