A019982 Decimal expansion of tangent of 84 degrees.

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

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• cons
• changed

Comments

Also the decimal expansion of cotangent of 6 degrees. - Ivan Panchenko, Sep 01 2014

Examples

			tan(7*Pi/15) = 9.5143644...
		

Links

• Ivan Panchenko, Table of n, a(n) for n = 1..1000
• Wikipedia, Exact trigonometric constants.
• Index entries for algebraic numbers, degree 8

Crossrefs

Cf. A019970, A019976.

Programs

Mathematica

RealDigits[Tan[7*Pi/15], 10, 100][[1]] (* Amiram Eldar, Apr 07 2022 *)

Formula

From Amiram Eldar, Apr 07 2022: (Start)

Equals tan(78 degrees) + tan(72 degrees) + tan(60 degrees).

Equals sqrt(23 + 10*sqrt(5) + 2*sqrt(3*(85 + 38*sqrt(5)))).

The 4th positive and largest root of x^8 - 92*x^6 + 134*x^4 - 28*x^2 + 1 = 0. (End)

Equals A019893/A019815. - R. J. Mathar, Sep 06 2025