Trigonometryhard · Past Paper
What is the value of sin 18?
A(sqrt(5)-1)/4
B(sqrt(5)+1)/4
Csqrt(10 - 2sqrt(5))/4
D1/4
✓ Correct Answer: A — (sqrt(5)-1)/4
Derived using 2A = 90 - 3A, sin 18 is (sqrt(5)-1)/4.
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