A019815 Decimal expansion of sine of 6 degrees.

1, 0, 4, 5, 2, 8, 4, 6, 3, 2, 6, 7, 6, 5, 3, 4, 7, 1, 3, 9, 9, 8, 3, 4, 1, 5, 4, 8, 0, 2, 4, 9, 8, 1, 1, 9, 0, 8, 0, 6, 5, 5, 8, 6, 9, 4, 7, 4, 5, 9, 3, 1, 1, 3, 9, 9, 3, 2, 7, 5, 4, 7, 6, 7, 1, 2, 4, 8, 4, 6, 5, 0, 6, 9, 3, 1, 8, 0, 0, 4, 6, 8, 2, 8, 1, 8, 0, 3, 9, 8, 7, 9, 8, 6, 0, 4, 4, 2, 6

Offset

0,3

Comments

Decimal expansion of 1/8 (-1 - sqrt(5) + sqrt(6*(5 - sqrt(5)))). - Artur Jasinski, Oct 28 2008

Links

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Wikipedia, Exact trigonometric constants

Index entries for algebraic numbers, degree 4

Formula

Equals cos(7*Pi/15) = -cos(8*Pi/15) = 2F1(6/5,-1/5;1/2;3/4) / 2 = -2F1(13/10,-3/10;1/2;3/4) / 2. - R. J. Mathar, Oct 27 2008

Equals 2*A019812*A019896. - R. J. Mathar, Jan 17 2021

Example

0.10452846...

Mathematica

First[RealDigits[1/8 (-1 - Sqrt[5] + Sqrt[6 (5 - Sqrt[5])]), 10, 100]] (* Artur Jasinski, Oct 28 2008 *)
RealDigits[Sin[6 Degree], 10, 120][[1]] (* Harvey P. Dale, Apr 27 2012 *)

Prog

(PARI) sin(Pi/30) \\ Charles R Greathouse IV, Jan 30 2016

Crossrefs

Sequence in context: A356151 A194880 A111624 * A281143 A200684 A345210

Adjacent sequences: A019812 A019813 A019814 * A019816 A019817 A019818

Keyword

nonn,cons

Author

N. J. A. Sloane

Status

approved