A019884 - OEIS

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A019884

Decimal expansion of sine of 75 degrees.

17

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

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OFFSET

0,1

COMMENTS

Also the real part of i^(1/6). - Stanislav Sykora, Apr 25 2012

Length of one side of the new Type 15 Convex Pentagon. - Michel Marcus, Aug 04 2015

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Casey Mann et al, Type 15 Convex Pentagon, Jul 29 2015.

Wikipedia, Trigonometric constants expressed in real radicals.

Index entries for algebraic numbers, degree 4

FORMULA

Equals cos(Pi/12) = [1+sqrt(3)]/[2*sqrt(2)] = A090388 * A020765. - R. J. Mathar, Jun 18 2006

Equals A019859 * A019874 + A019834 * A019849 = A019881 * A019896 + A019812 * A019827 . - R. J. Mathar, Jan 27 2021

Equals 1/(sqrt(6) - sqrt(2)) = 1/A120683. - Amiram Eldar, Aug 04 2022

Largest of the 4 real-valued roots of 16*x^4 -16*x^2 +1=0. - R. J. Mathar, Aug 29 2025

4*this^3 -3*this = A010503. - R. J. Mathar, Aug 29 2025

Equals 2F1(-1/8,1/8 ;1/2;3/4) = 2F1(-1/6,1/6;1/2;1/2). - R. J. Mathar, Aug 31 2025

EXAMPLE

0.96592582628906828674974319972889736763390483900840455040234307631042...

MATHEMATICA

RealDigits[Sin[75 Degree], 10, 100][[1]] (* Vincenzo Librandi, Aug 11 2014 *)

PROG

(PARI) cos(Pi/12) \\ Charles R Greathouse IV, Apr 25 2012

CROSSREFS

Sequence in context: A019942 A102047 A144665 * A103814 A245770 A117020

Adjacent sequences: A019881 A019882 A019883 * A019885 A019886 A019887

KEYWORD

nonn,cons

AUTHOR

N. J. A. Sloane

STATUS

approved