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 A198127 #6 Feb 07 2025 16:44:04
%S A198127 6,8,7,2,2,8,2,9,2,2,5,2,5,4,8,8,5,4,0,1,5,3,6,6,7,6,6,9,9,7,6,1,9,0,
%T A198127 5,2,1,7,1,1,1,6,2,1,1,9,2,3,5,6,6,2,5,0,8,5,0,8,0,1,0,4,6,0,3,6,6,6,
%U A198127 7,9,0,0,1,1,4,7,5,2,4,3,9,0,6,9,9,0,9,2,7,7,9,3,6,1,8,3,3,8,1
%N A198127 Decimal expansion of greatest x having 2*x^2+2x=3*cos(x).
%C A198127 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198127 least x: -1.303688236082731236157942349201731581...
%e A198127 greatest x: 0.68722829225254885401536676699761905...
%t A198127 a = 2; b = 2; c = 3;
%t A198127 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198127 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198127 r1 = x /. FindRoot[f[x] == g[x], {x, -1.31, -1.30}, WorkingPrecision -> 110]
%t A198127 RealDigits[r1] (* A198126 *)
%t A198127 r2 = x /. FindRoot[f[x] == g[x], {x, .68, .69}, WorkingPrecision -> 110]
%t A198127 RealDigits[r2] (* A198127 *)
%Y A198127 Cf. A197737.
%K A198127 nonn,cons
%O A198127 0,1
%A A198127 _Clark Kimberling_, Oct 22 2011