Question

ifsin theta + cos2 theta = 1 , then find the value of cos2 theta + cos4 theta​ only verified answers​ tumese kisi Ke bas ki baat nhi hai​

Answer 1

Step-by-step explanation:

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

Answer 2

Answer:

Given, sinθ+sin²θ=1

⇒sinθ=1−sin²θ=cos²θ

Therefore, cos²θ+cos⁴θ=cos²θ(1+cos²θ)

=sinθ(1+sinθ)

=sinθ+sin²θ=1