Question

sin⁴a+cos⁴a+2sin²a×cos²a​

Answer 1

(a + b)^2 = a^2 +2ab + b^2
sin^4(A) + cos^4(A)+2sin^2(A)*cos^2(A) =
= (sin^2(A) + cos^2(A))^2 = 1^2 = 1