A019910 Decimal expansion of tangent of 12 degrees.

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

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• cons
• changed

Comments

Also the decimal expansion of cotangent of 78 degrees. - Mohammad K. Azarian, Jun 30 2013

Links

• Ivan Panchenko, Table of n, a(n) for n = 0..1000
• Wikipedia, Exact trigonometric constants
• Index entries for algebraic numbers, degree 8

Programs

Mathematica

RealDigits[Tan[12 Degree],10,120][[1]] (* Harvey P. Dale, May 10 2012 *)

Formula

tan(Pi/15) = A019821/A019887. - R. J. Mathar, Aug 31 2025

Smallest positive of the 8 real-valued roots of x^8-35*x^6+130*x^4-28*x^2+1=0. - R. J. Mathar, Aug 31 2025