

A019845


Decimal expansion of sine of 36 degrees.


8



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

0,1


COMMENTS

This sequence is also decimal expansion of cosine of 54 degrees.  Mohammad K. Azarian, Jun 29 2013
The ratio of side to longer diagonal for any golden rhombus (see A019881).  Rick L. Shepherd, Apr 10 2017


LINKS

Zak Seidov, Table of n, a(n) for n = 0..999
Wikipedia, Exact trigonometric constants


FORMULA

sin 36 degrees = sin Pi/5 radians = sqrt((1/8)(5  sqrt(5))).
Equals A019881/A001622.  Rick L. Shepherd, Apr 10 2017
This constant is (1/2)*A182007.  Wolfdieter Lang, May 08 2018


EXAMPLE

sin 36 degrees = 0.587785252292473129168705954639...


MATHEMATICA

RealDigits[Sin[Pi/5], 10, 100][[1]] (* Alonso del Arte, Sep 19 2017 *)
RealDigits[Sin[36 Degree], 10, 120][[1]] (* Harvey P. Dale, Aug 14 2018 *)


PROG

(PARI) sin(Pi/5) \\ Michel Marcus, Apr 25 2015
(PARI) cos(3*Pi/10) \\ Rick L. Shepherd, Apr 10 2017
(PARI) real(I^(3/5)) \\ Rick L. Shepherd, Apr 10 2017


CROSSREFS

Cf. A019827 (sine of 18 degrees), A019881 (sine of 72 degrees), A001622 (golden ratio phi). A182007.
Sequence in context: A243598 A230366 A197415 * A143618 A177056 A053787
Adjacent sequences: A019842 A019843 A019844 * A019846 A019847 A019848


KEYWORD

nonn,cons,easy


AUTHOR

N. J. A. Sloane.


STATUS

approved



