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Which expression equals cos²A?
A(1 − cos 2A)/2
B(1 + cos 2A)/2
C(1 + sin 2A)/2
D1 + cos 2A
Answer & Solution
Correct answer: B. (1 + cos 2A)/2
Solving cos 2A = 2cos²A − 1 for cos²A gives (1 + cos 2A)/2.
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