Question

1 + cos²2x= 2(cos⁴x + sin⁴x)

Answer 1

Answer:

2(cos⁴x+sin⁴x)

2((sin²x+cos²x)²-2sin²xcos²x

2(1-1/2(sin2x)²)

2(1-1/2(1-cos²2x)

1+cos²2x