sin4θ + cos4θ in terms of sinθ can be written as:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 2sin4θ - 2sin2θ + 1.
Formula used:
Cos2θ = 1 - sin2θ
Calculations:
⇒ sin4θ + cos4θ
Can be written as
⇒ sin4θ + (cos2θ)2
⇒ sin4θ + (1 - sin2θ)2
⇒ sin4θ + 1 + sin4θ - 2sin2θ
⇒ 2sin4θ - 2sin2θ + 1