cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A199731 Decimal expansion of least x satisfying x^2-4*x*cos(x)=4*sin(x).

Original entry on oeis.org

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

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Author

Clark Kimberling, Nov 09 2011

Keywords

Comments

See A199597 for a guide to related sequences. The Mathematica program includes a graph.

Examples

			least: -3.80284270062359171640437975188554983520...
greatest:  1.71776170155914673794654693768308401...
		

Crossrefs

Cf. A199597.

Programs

  • Mathematica
    a = 1; b = -4; c = 4;
    f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c*Sin[x]
    Plot[{f[x], g[x]}, {x, -2 Pi, Pi}, {AxesOrigin -> {0, 0}}]
    r = x /. FindRoot[f[x] == g[x], {x, -3.9, -3.8}, WorkingPrecision -> 110]
    RealDigits[r]   (* A199731 least of 4 roots *)
    r = x /. FindRoot[f[x] == g[x], {x, 1.71, 1.72}, WorkingPrecision -> 110]
    RealDigits[r]   (* A199732 greatest of 4 roots *)