A019940 Decimal expansion of tangent of 42 degrees.

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

Offset

0,1

Comments

Also the decimal expansion of cotangent of 48 degrees. - Ivan Panchenko, Sep 01 2014

Links

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Wikipedia, Exact trigonometric constants

Formula

Equals sqrt(7 + 2*sqrt(5) - 2*sqrt(3*(5 + 2*sqrt(5)))). - G. C. Greubel, Nov 25 2018

Example

0.900404044297839945120477203885371702076466211299485282427079...

Mathematica

RealDigits[Tan[42 Degree], 10, 120][[1]] (* Harvey P. Dale, Sep 05 2012 *)
RealDigits[Tan[7*Pi/30], 10, 100][[1]] (* G. C. Greubel, Nov 25 2018 *)

Prog

(PARI) default(realprecision, 100); tan(7*Pi/30) \\ G. C. Greubel, Nov 25 2018
(Magma) SetDefaultRealField(RealField(100)); R:= RealField(); Tan(7*Pi(R)/30); // G. C. Greubel, Nov 25 2018
(Sage) numerical_approx(tan(7*pi/30), digits=100) # G. C. Greubel, Nov 25 2018

Crossrefs

Cf. A019851 (sine of 42 degrees)

Sequence in context: A112628 A198871 A254968 * A257435 A366193 A296458

Adjacent sequences: A019937 A019938 A019939 * A019941 A019942 A019943

Keyword

nonn,cons

Author

N. J. A. Sloane

Status

approved