A195702 Decimal expansion of arccos(-sqrt(2/3)).

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

Offset

1,1

Links

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

Formula

Equals Pi - arcsin(sqrt(1/3)) = Pi - arctan(sqrt(1/2)). - Amiram Eldar, Jul 10 2023

Example

arccos(-sqrt(2/3)) = 2.5261129449405...

Mathematica

r = Sqrt[2/3];
N[ArcSin[r], 100]
RealDigits[%]  (* A195696 *)
N[ArcCos[r], 100]
RealDigits[%]  (* A195695 *)
N[ArcTan[r], 100]
RealDigits[%]  (* A195701 *)
N[ArcCos[-r], 100]
RealDigits[%]  (* A195702 *)
RealDigits[ArcCos[-Sqrt[(2/3)]], 10, 120][[1]] (* Harvey P. Dale, Jan 15 2013 *)

Prog

(PARI) acos(-sqrt(2/3)) \\ G. C. Greubel, Nov 18 2017
(Magma) [Arccos(-Sqrt(2/3))]; // G. C. Greubel, Nov 18 2017

Crossrefs

Cf. A195701.

Sequence in context: A198604 A198253 A159989 * A309714 A309431 A344077

Adjacent sequences: A195699 A195700 A195701 * A195703 A195704 A195705

Keyword

nonn,cons

Author

Clark Kimberling, Sep 23 2011

Status

approved