A195704 Decimal expansion of arccos(-sqrt(1/8)).

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

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..5000

Formula

Equals Pi - arcsin(sqrt(7/2)/2) = Pi - arctan(sqrt(7)). - Amiram Eldar, Jul 09 2023

Example

arccos(-sqrt(1/8)) = 1.93216345070...

Mathematica

r = Sqrt[1/8];
N[ArcSin[r], 100]
RealDigits[%]  (* A195699 *)
N[ArcCos[r], 100]
RealDigits[%]  (* A168229 *)
N[ArcTan[r], 100]
RealDigits[%]  (* A188615 *)
N[ArcCos[-r], 100]
RealDigits[%]  (* A195704 *)

Prog

(PARI) acos(-sqrt(1/8)) \\ G. C. Greubel, Nov 18 2017
(Magma) [Arccos(-Sqrt(1/8))]; // G. C. Greubel, Nov 18 2017

Crossrefs

Cf. A195699.

Sequence in context: A086232 A133867 A210113 * A176516 A337768 A210644

Adjacent sequences: A195701 A195702 A195703 * A195705 A195706 A195707

Keyword

nonn,cons

Author

Clark Kimberling, Sep 23 2011

Status

approved