Answer:
cos(2x)
Explanation:
To simplify the expression cos²x - sin²x, we can use the identity cos²x - sin²x = cos(2x).
This identity can be derived by using the double angle formula for cosine:
cos(2x) = cos(x + x) = cos(x)cos(x) - sin(x)sin(x) = cos²x - sin²x
Therefore, the expression cos²x - sin²x can be simplified to cos(2x).