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.
%I A197815 #6 Feb 07 2025 16:44:04
%S A197815 5,8,9,3,0,3,2,0,8,1,5,9,0,1,2,8,7,4,7,2,5,2,2,3,9,1,9,0,7,3,8,6,9,1,
%T A197815 8,5,8,8,9,0,6,0,9,8,8,0,5,4,0,7,0,3,0,5,5,3,9,2,1,4,0,7,5,1,1,7,1,4,
%U A197815 5,7,1,7,7,0,6,4,7,2,4,1,0,8,8,0,5,2,2,1,0,2,0,0,1,6,9,6,5,6,7
%N A197815 Decimal expansion of least x having x^2-2x=-cos(x).
%C A197815 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A197815 least x: 0.589303208159012874725223919073869185889...
%e A197815 greatest x: 2.287086177656584485337033312314491737...
%t A197815 a = 1; b = -2; c = -1;
%t A197815 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A197815 Plot[{f[x], g[x]}, {x, -1, 3}]
%t A197815 r1 = x /. FindRoot[f[x] == g[x], {x, .5, .6}, WorkingPrecision -> 110]
%t A197815 RealDigits[r1] (* A197815 *)
%t A197815 r2 = x /. FindRoot[f[x] == g[x], {x, 2.2, 2.3}, WorkingPrecision -> 110]
%t A197815 RealDigits[r2] (* A197820 *)
%Y A197815 Cf. A197737.
%K A197815 nonn,cons
%O A197815 0,1
%A A197815 _Clark Kimberling_, Oct 20 2011