Question

cos^6a+sin^6a=1-3/4sin^2a
prove it​

Answer 1

Answer:

2 this is the correct answer may be

Answer 2

Answer:1- $\frac{3}{4\\}$sin²2a

Step-by-step explanation:

L.H.S

= cos⁶a+sin⁶a

= (cos²a)³+(sin²a)³

= (cos²a+sin²a) (cos⁴a-sin²a×cos²a+sin⁴a)

= 1 {(cos²a)²+(sin²a)²-sin²a×cos²a}

= (cos²a+sin²a)²-2sin²a×cos²a-sin²a×cos²a

= 1²-3sin²a×cos²a

= 1- $\frac{3.4}{4}$sin²a×cos²a

= 1- $\frac{3}{4}$ (2sina×cosa)²

= 1- $\frac{3}{4}$sin²2a