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A197809 Decimal expansion of x<0 having x^2+x=2*cos(x). 3
1, 3, 4, 0, 5, 2, 5, 3, 0, 8, 1, 9, 7, 3, 9, 8, 4, 4, 7, 8, 6, 7, 6, 0, 6, 2, 8, 4, 9, 9, 6, 0, 6, 6, 0, 9, 2, 0, 5, 8, 3, 4, 1, 8, 6, 8, 9, 3, 1, 2, 0, 4, 5, 7, 5, 5, 2, 4, 7, 3, 5, 7, 7, 3, 0, 0, 2, 1, 3, 0, 7, 8, 1, 3, 0, 4, 2, 1, 6, 6, 7, 3, 0, 3, 4, 7, 6, 9, 9, 7, 5, 6, 5, 9, 9, 9, 0, 8, 2 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A197737 for a guide to related sequences.  The Mathematica program includes a graph.

LINKS

Table of n, a(n) for n=1..99.

EXAMPLE

negative: -1.3405253081973984478676062849960660920583...

positive:  0.7883968459929654290788209839820019122955...

MATHEMATICA

a = 1; b = 1; c = 2;

f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]

Plot[{f[x], g[x]}, {x, -2, 1.5}]

r1 = x /. FindRoot[f[x] == g[x], {x, -1.5, -1.3}, WorkingPrecision -> 110]

RealDigits[r1] (* A197809 *)

r2 = x /. FindRoot[f[x] == g[x], {x, .78, .79}, WorkingPrecision -> 110]

RealDigits[r2] (* A197810 *)

CROSSREFS

Cf. A197738.

Sequence in context: A267183 A021750 A246770 * A086230 A197485 A158677

Adjacent sequences:  A197806 A197807 A197808 * A197810 A197811 A197812

KEYWORD

nonn,cons

AUTHOR

Clark Kimberling, Oct 20 2011

STATUS

approved

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Last modified May 23 22:33 EDT 2022. Contains 353993 sequences. (Running on oeis4.)