A197376 Decimal expansion of least x>0 having sin(x)=(sin (x/2))^2.
2, 2, 1, 4, 2, 9, 7, 4, 3, 5, 5, 8, 8, 1, 8, 1, 0, 0, 6, 0, 3, 4, 1, 3, 0, 9, 2, 0, 3, 5, 7, 0, 7, 4, 0, 8, 0, 1, 4, 0, 0, 9, 5, 2, 9, 0, 8, 0, 2, 8, 6, 5, 2, 9, 3, 3, 5, 3, 0, 7, 8, 4, 1, 4, 8, 6, 7, 4, 2, 0, 6, 7, 7, 9, 5, 4, 7, 2, 5, 5, 8, 8, 0, 2, 6, 8, 3, 4, 2, 5, 7, 3, 7, 2, 3, 4, 1, 2, 8
Offset: 1
Examples
2.2142974355881810060341309203570740...
Crossrefs
Cf. A197133.
Programs
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Mathematica
b = 1; c = 1/2; f[x_] := Sin[x] t = x /. FindRoot[f[b*x] == f[c*x]^2, {x, 2, 2.5}, WorkingPrecision -> 200] RealDigits[t] (* *) Plot[{f[b*x], f[c*x]^2}, {x, 0, 2.5}] RealDigits[ 2*ArcCos[ 1/Sqrt[5] ], 10, 99] // First (* Jean-François Alcover, Feb 19 2013 *)
Formula
Equals 2*A105199. - R. J. Mathar, Aug 27 2024
Comments