Question

Sin4A+Cos4A. = 1/2(2-sin22A)

Answer 1

Answer:

sin⁴A+cos⁴A

=(sin²A+cos²A)²-2sin²A cos²A

=1-2sin²A cos²A

=1/2(2-4sin²A cos²A)

=1/2{2-(sin2A)²}