Question

cos^4θ-sin^4θ equals to ?

Answer 1

the answer is 40£>...



..

Answer 2

Step-by-step explanation:

sin

4

θ+cos

4

θ−2sin

2

θcos

2

θ=1−4sin

2

θcos

2

θ

=(sin

2

θ+cos

2

θ)

2

−2sin

2

θcos

2

θ−2sin

2

θcos

2

θ

=(sin

2

θ+cos

2

θ)

2

−4sin

2

θcos

2

θ

=(1)

2

−4sin

2

θcos

2

θ since sin

2

θ+cos

2

θ=1

=1−4sin

2

θcos

2

θ