Correct option is A
Given:
If sin θ - cos θ = 0 then the value of (sin4θ + cos 4θ) is -------------?
Formula used:
sin 45°=21
cos 45°=21
Solution:
sin θ - cos θ = 0
sin θ = cos θ
Hence,
θ=45°
Therefore.
(sin4θ + cos4θ)
= sin445∘+cos445∘
= (21)4+(21)4
= 41+41
= 42
= 21
Thus, the correct answer is (a).