The exact values of and can be given by infinite nested radicals
where the sequence of signs +, +, repeats with period 3, and
where the sequence of signs , , + repeats with period 3.
The exact values of and can be given by infinite nested radicals
where the sequence of signs +, +, repeats with period 3, and
where the sequence of signs , , + repeats with period 3.
Weisstein, Eric W. "Trigonometry Angles--Pi/18." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/TrigonometryAnglesPi18.html