Final answer:
The expression cos2A represents the square of the cosine of angle A. Option B, 1 - 2sin2A, is not equivalent to cos2A.
Step-by-step explanation:
The expression cos2A represents the square of the cosine of angle A. To determine which of the given options is not equivalent to cos2A, we can compare them to the trigonometric identities involving cosine and sine.
We have cos2A - sin2A = 1 - 2sin2A, which matches option B. Therefore, option B, 1 - 2sin2A, is not equivalent to cos2A.