A019961 Decimal expansion of tangent of 63 degrees.

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

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• cons
• changed

Comments

Also the decimal expansion of cotangent of 27 degrees. - Ivan Panchenko, Sep 01 2014

Examples

			1.96261050550515058230464042621189498505671...
		

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. A019872 (sine of 63 degrees).

Programs

Magma

SetDefaultRealField(RealField(100)); R:= RealField(); Tan(7*Pi(R)/20); // G. C. Greubel, Nov 21 2018

Mathematica

RealDigits[Tan[7*Pi/20], 10, 100][[1]] (* G. C. Greubel, Nov 21 2018 *)

PARI

default(realprecision, 100); tan(7*Pi/20) \\ G. C. Greubel, Nov 21 2018

Sage

numerical_approx(tan(7*pi/20), digits=100) # G. C. Greubel, Nov 21 2018

Formula

Equals cot(3*Pi/20) = sqrt(5) - 1 + sqrt(5 - 2*sqrt(5)). - G. C. Greubel, Nov 21 2018

Root of x^8-44*x^6+166*x^4-44*x^2+1=0. - R. J. Mathar, Aug 31 2025