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Trigonometry Angles--Pi/12


cos(pi/(12))=1/4(sqrt(6)+sqrt(2))
(1)
cos((5pi)/(12))=1/4(sqrt(6)-sqrt(2))
(2)
cot(pi/(12))=2+sqrt(3)
(3)
cot((5pi)/(12))=2-sqrt(3)
(4)
csc(pi/(12))=sqrt(6)+sqrt(2)
(5)
csc((5pi)/(12))=sqrt(6)-sqrt(2)
(6)
sec(pi/(12))=sqrt(6)-sqrt(2)
(7)
sec((5pi)/(12))=sqrt(6)+sqrt(2)
(8)
sin(pi/(12))=1/4(sqrt(6)-sqrt(2))
(9)
sin((5pi)/(12))=1/4(sqrt(6)+sqrt(2))
(10)
tan(pi/(12))=2-sqrt(3)
(11)
tan((5pi)/(12))=2+sqrt(3).
(12)

These can be derived using

sin(pi/(12))=sin(pi/3-pi/4)
(13)
=-sin(pi/4)cos(pi/3)+sin(pi/3)cos(pi/4)
(14)
=-1/2sqrt(2)(1/2)+1/2sqrt(3)(1/2sqrt(2))
(15)
=1/4(sqrt(6)-sqrt(2)).
(16)

Similarly,

cos(pi/(12))=cos(pi/3-pi/4)
(17)
=cos(pi/4)cos(pi/3)-sin(pi/3)sin(pi/4)
(18)
=1/2(1/2sqrt(2))+1/2sqrt(3)(-1/2sqrt(2))
(19)
=1/4(sqrt(6)+sqrt(2)).
(20)

See also

Trigonometry Angles, Trigonometry, Trigonometry Angles--Pi/3, Trigonometry Angles--Pi/4, Trigonometry Angles--Pi/6

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Cite this as:

Weisstein, Eric W. "Trigonometry Angles--Pi/12." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/TrigonometryAnglesPi12.html

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