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 A198237 #6 Feb 07 2025 16:44:05
%S A198237 2,1,1,0,4,7,2,9,4,4,9,0,0,4,0,2,8,4,2,0,8,2,1,9,2,9,2,6,6,0,1,9,0,8,
%T A198237 2,8,8,0,8,4,5,8,3,4,0,1,0,3,0,2,3,9,4,9,9,4,3,9,5,2,1,7,4,2,3,5,6,7,
%U A198237 1,9,7,8,1,2,9,8,7,1,4,9,3,9,2,3,8,1,5,5,4,6,8,2,7,8,7,6,1,0,7
%N A198237 Decimal expansion of greatest x having 3*x^2+4x=cos(x).
%C A198237 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198237 least x: -1.379323320986887658637256189560173787662...
%e A198237 greatest x: 0.2110472944900402842082192926601908288...
%t A198237 a = 3; b = 4; c = 1;
%t A198237 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198237 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198237 r1 = x /. FindRoot[f[x] == g[x], {x, -1.4, -1.3}, WorkingPrecision -> 110]
%t A198237 RealDigits[r1](* A198236 *)
%t A198237 r2 = x /. FindRoot[f[x] == g[x], {x, .21, .22}, WorkingPrecision -> 110]
%t A198237 RealDigits[r2] (* A198237 *)
%Y A198237 Cf. A197737.
%K A198237 nonn,cons
%O A198237 0,1
%A A198237 _Clark Kimberling_, Oct 23 2011