Question

if sin theta + sin² theta =1 , then cos²theta +cos ^4 theta =​

Answer 1

Given, sinθ+sin

2

θ=1

⇒sinθ=1−sin

2

θ=cos

2

θ

Therefore, cos

2

θ+cos

4

θ=cos

2

θ(1+cos

2

θ)

=sinθ(1+sinθ)

=sinθ+sin

2

θ

=1