A343061 Decimal expansion of tan(Pi/17).

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

Offset: 0

Author

Seiichi Manyama, Apr 04 2021

Keywords

• nonn
• cons
• easy
• changed

Comments

Root of the equation 17 - 680*x^2 + 6188*x^4 - 19448*x^6 + 24310*x^8 - 12376*x^10 + 2380*x^12 - 136*x^14 + x^16 = 0. - Vaclav Kotesovec, Apr 04 2021

Examples

			0.18693239710797714594807628412307...
		

Links

• Index entries for algebraic numbers, degree 16

Crossrefs

Cf. A241243 (sin(Pi/17)), A210649 (cos(Pi/17)).

Programs

Mathematica

RealDigits[Tan[Pi/17], 10, 100][[1]] (* Amiram Eldar, Apr 27 2021 *)

PARI

tan(Pi/17)

Formula

Equals sqrt((-2*(-8 + sqrt(2*(15 + sqrt(17) - sqrt(34 - 2*sqrt(17)) + sqrt(2*(34 + 6*sqrt(17) - sqrt(578 - 34*sqrt(17)) + sqrt(34 - 2*sqrt(17)) + 8*sqrt(2*(17 + sqrt(17)))))))))/(15 + sqrt(17) + sqrt(34 - 2*sqrt(17)) + sqrt(2*(34 + 6*sqrt(17) + sqrt(578 - 34*sqrt(17)) - sqrt(34 - 2*sqrt(17)) - 8*sqrt(2*(17 + sqrt(17))))))). - Vaclav Kotesovec, Apr 04 2021