Trigonometry Angles--Pi/20

Values of the trigonometric functions can be expressed exactly for integer multiples of . For ,

			(1)
			(2)
			(3)
			(4)

for ,

			(5)
			(6)
			(7)
			(8)

for ,

			(9)
			(10)
			(11)
			(12)

for ,

			(13)
			(14)
			(15)
			(16)

for ,

			(17)
			(18)
			(19)
			(20)

and for ,

			(21)
			(22)
			(23)
			(24)

These can be derived from the half-angle formulas

			(25)
			(26)
			(27)
			(28)
			(29)
			(30)
			(31)