A375192 Decimal expansion of the sagitta of a regular 11-gon with unit side length.

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

Offset

-1,1

Links

Paolo Xausa, Table of n, a(n) for n = -1..10000

Eric Weisstein's World of Mathematics, Regular Polygon.

Eric Weisstein's World of Mathematics, Sagitta.

Index entries for algebraic numbers, degree 10.

Formula

Equals tan(Pi/22)/2.

Equals A375190 - A375191.

Minimal polynomial: 11264*x^10 - 42240*x^8 + 29568*x^6 - 5280*x^4 + 220*x^2 - 1. - Amiram Eldar, Jun 06 2026

Example

0.0718891469974866583327667878445514301267263890621...

Mathematica

First[RealDigits[Tan[Pi/22]/2, 10, 100]]

Prog

(PARI) tan(Pi/22)/2 \\ Charles R Greathouse IV, Feb 04 2025
(PARI) polrootsreal(11264*x^10-42240*x^8+29568*x^6-5280*x^4+220*x^2-1)[6] \\ Charles R Greathouse IV, Feb 04 2025

Crossrefs

Cf. A375190 (circumradius), A375191 (apothem), A256854 (area).

Cf. sagitta of other polygons with unit side length: A020769 (triangle), A174968 (square), A375068 (pentagon), A375069 (hexagon), A374972 (heptagon), A375070 (octagon), A375153 (9-gon), A375189 (10-gon), A375194 (12-gon).

Sequence in context: A244382 A378013 A111293 * A019661 A200130 A298751

Adjacent sequences: A375189 A375190 A375191 * A375193 A375194 A375195

Keyword

nonn,cons,easy

Author

Paolo Xausa, Aug 04 2024

Status

approved