Trigonometrymedium · Past Paper
Which formula represents cos 3A?
A3 cos A - 4 cos³ A
B4 cos³ A - 3 cos A
C3 cos³ A - 4 cos A
D4 cos A - 3 cos³ A
✓ Correct Answer: B — 4 cos³ A - 3 cos A
This is the standard triple angle formula for cosine.
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