A201680 Decimal expansion of least x satisfying 10*x^2 - 1 = csc(x) and 0<x<Pi.

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

Offset

0,1

Comments

See A201564 for a guide to related sequences. The Mathematica program includes a graph.

Links

G. C. Greubel, Table of n, a(n) for n = 0..10000

Example

least:  0.54206448268216048375504315216947653357...
greatest:  3.13128846969356249380458505204753587...

Mathematica

a = 10; c = -1;
f[x_] := a*x^2 + c; g[x_] := Csc[x]
Plot[{f[x], g[x]}, {x, 0, Pi}, {AxesOrigin -> {0, 0}}]
r = x /. FindRoot[f[x] == g[x], {x, .5, .6}, WorkingPrecision -> 110]
RealDigits[r]     (* A201680 *)
r = x /. FindRoot[f[x] == g[x], {x, 3.0, 3.14}, WorkingPrecision -> 110]
RealDigits[r]     (* A201681 *)

Prog

(PARI) a=10; c=-1; solve(x=0.5, 1, a*x^2 + c - 1/sin(x)) \\ G. C. Greubel, Sep 12 2018

Crossrefs

Cf. A201564.

Sequence in context: A279151 A224228 A286680 * A349409 A109430 A085917

Adjacent sequences: A201677 A201678 A201679 * A201681 A201682 A201683

Keyword

nonn,cons

Author

Clark Kimberling, Dec 04 2011

Status

approved