Question

(sin^2a)^2+(cos^2a)^2​

Answer 1

(sin²a)²+ (cos²a)²

(1-cos²a)^²+ (cos²a)²

1-2cos⁴a+ cos⁴a+ cos⁴a

1-2cos⁴a+2cos⁴a

=> 1

instruction

(a-b)² =>a²-2ab+b²

(cos²a)²= cos⁴a

1-cos²a= sin²a