Question

if cos6 theta=a cos raised to6 theta+ b cos 4 raised to theta* sin raised to 3 theta+ c cos raised to 2 theta* sin raised to 4 theta + d sin raised to 6 theta, find a, b, c, d

Answer 1

Step-by-step explanation:

sin

6

θ+cos

6

θ+3sin

2

θcos

2

θ

⇒LHS=(sin

2

θ)

3

+(cos

2

θ)

3

+3sin

2

θcos

2

θ

Using, [a

3

+b

3

=(a+b)

3

−3ab(a+b)]

⇒LHS=(sin

2

θ+cos

2

θ)

3

−3sin

2

θcos

2

θ(sin

2

θ+cos

2

θ)

3

+3sin

2

θcos

2

θ

⇒LHS=1−3sin

2

θcos

2

θ+3sin

2

θcos

2

θ=1=RHS