Trigonometryhard · Past Paper
What is the value of sin 18°?
A(√5 - 1) / 4
B(√5 + 1) / 4
C√(10 - 2√5) / 4
D√(10 + 2√5) / 4
✓ Correct Answer: A — (√5 - 1) / 4
This is a standard derived value in trigonometry using the multiple angle 5θ = 90°.
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