Trigonometryhard · Past Paper
If cos θ = 2/3, evaluate 9 tan²θ - 1.
A10.25
B11.5
C10
D12
✓ Correct Answer: A — 10.25
tan²θ = sec²θ - 1 = 9/4 - 1 = 5/4. 9(5/4) - 1 = 45/4 - 1 = 11.25 - 1 = 10.25.
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