Question

cos^A6+sin^6A=1/8(5+3cos4A) prove it​

Answer 1

Answer:

cos

6

α+sin

6

α+ksin

2

2α=1

⇒(cos

2

α)

3

+(sin

2

α)

3

+ksin

2

2α=1

⇒1−3sin

2

αcos

2

α+ksin

2

2α=1

⇒1−

4

3

sin

2

2α+ksin

2

2α=1

⇒1+sin

2

2α(k−

4

3

)=1

⇒k=

4

3