Trigonometry Angles—Pi/20

Author

Eric W. Weisstein
October 9, 2007

This notebook downloaded from http://mathworld.wolfram.com/notebooks/Trigonometry/TrigonometryAnglesPi20.nb.

For more information, see Eric's MathWorld entry http://mathworld.wolfram.com/TrigonometryAnglesPi20.html.

©2007 Wolfram Research, Inc. except for portions noted otherwise

Initialization

<<Utilities`Simplify`

Values

a=Select[Range[10],GCD[#,20]==1&]

(values=Flatten[Map[{#,SqrtSimplify[ExpandAll[FullSimplify[RootReduce[Developer`TrigToRadicals[#]]]]]}&,Transpose[Through[{Cos,Cot,Csc,Sec,Sin,Tan}[#Pi/20]]&/@a],
{2}],1])//ColumnForm

Check

Chop[Subtract@@@N[values]]