Trigonometrymedium · Past Paper
Simplify cos^4 A - sin^4 A.
A1
Bcos(2A)
Csin(2A)
D0
✓ Correct Answer: B — cos(2A)
(cos^2 A - sin^2 A)(cos^2 A + sin^2 A) = cos(2A) * 1 = cos(2A).
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