sin4θ + cos4θ in terms of sinθ can be written as:
A. 2sin4θ + 2sin2θ - 1
B. 2sin4θ - 2sin2θ
C. 2sin4θ - 2sin2θ - 1
D. 2sin4θ - 2sin2θ + 1
Answer: Option D
Solution (By Examveda Team)
(sin2θ + cos2θ)2 = 1sin4θ + cos4θ + 2sin2θ.cos2θ = 1
sin4θ + cos4θ = 1 - 2sin2θ.cos2θ
sin4θ + cos4θ = 1 - 2sin2θ(1 - sin2θ)
sin4θ + cos4θ = 1 - 2sin2θ + 2sin4θ
This Question Belongs to Arithmetic Ability >> Trigonometry
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