A019875 Decimal expansion of sine of 66 degrees.
9, 1, 3, 5, 4, 5, 4, 5, 7, 6, 4, 2, 6, 0, 0, 8, 9, 5, 5, 0, 2, 1, 2, 7, 5, 7, 1, 9, 8, 5, 3, 1, 7, 1, 7, 7, 9, 4, 0, 8, 1, 0, 4, 5, 9, 3, 7, 7, 4, 7, 4, 5, 4, 5, 0, 6, 0, 9, 9, 9, 7, 8, 8, 0, 6, 5, 1, 1, 4, 8, 8, 2, 1, 0, 2, 6, 3, 1, 2, 7, 1, 6, 8, 1, 7, 8, 4, 0, 0, 0, 8, 9, 3, 2, 9, 9, 9, 9, 4
Offset: 0
Examples
0.913545457...
Links
- Ivan Panchenko, Table of n, a(n) for n = 0..1000
- Wikipedia, Exact trigonometric constants
- Index entries for algebraic numbers, degree 4
Programs
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Mathematica
RealDigits[N[Cos[2*Pi/15], 110]][[1]] (* Wesley Ivan Hurt, Dec 27 2021 *)
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PARI
cos(2*Pi/15) \\ Charles R Greathouse IV, Aug 27 2017
Formula
Largest of the 4 real-valued roots of 16*x^4-8*x^3-16*x^2+8*x+1=0. (Other A019851, -A019815, -A019887). - R. J. Mathar, Sep 04 2025
Comments