If θ be a positive acute angle satisfying sin2θ + sin4θ = 1; then the value of cot2θ + cot4θ is?

2 1 2\(\sqrt {2 }\) 0

1

sin2θ + sin4θ = 1 ⇒  sin4θ = 1 - sin2θ ⇒ sin4θ = cos2θ ⇒ tan2θsin2θ = 1 ⇒ cot2θ = sin2θ ∴ cot2θ + cot4θ = sin2θ + sin4θ = 1