Question

if sinθ+sin2θ=1 then cos2θ+cos4θ is equal to

Answer 1

sinθ+sin2θ=1
cos2θ+cos4θ = 0

hope helps

Answer 2

at theta = π/2

equation 1st satisfying

so Value

=> Cos2(π/2) + Cos4(π/2)

= Cosπ + Cos2π

= -1 + 1

= 0