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 A198360 #8 Feb 07 2025 16:44:05
%S A198360 5,8,0,4,5,7,1,2,4,4,4,5,9,3,3,1,6,1,7,9,7,2,1,9,6,5,1,4,2,8,8,1,9,0,
%T A198360 7,5,8,9,3,8,9,8,1,1,3,7,0,7,3,9,1,2,4,9,1,2,2,4,0,8,6,1,6,7,8,2,2,5,
%U A198360 7,9,9,5,6,9,8,9,0,1,5,7,4,9,9,8,9,7,4,5,1,3,3,1,9,1,6,1,8,0,9,6,6,5
%N A198360 Decimal expansion of greatest x having 4*x^2+2x=3*cos(x).
%C A198360 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198360 least x: -0.95434777660875567212090095479339137329...
%e A198360 greatest x: 0.58045712444593316179721965142881907589...
%t A198360 a = 4; b = 2; c = 3;
%t A198360 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198360 Plot[{f[x], g[x]}, {x, -1, 1}]
%t A198360 r1 = x /. FindRoot[f[x] == g[x], {x, -1, -.9}, WorkingPrecision -> 110]
%t A198360 RealDigits[r1] (* A198359 *)
%t A198360 r2 = x /. FindRoot[f[x] == g[x], {x, .58, .59}, WorkingPrecision -> 110]
%t A198360 RealDigits[r2] (* A198360 *)
%Y A198360 Cf. A197737.
%K A198360 nonn,cons
%O A198360 0,1
%A A198360 _Clark Kimberling_, Oct 24 2011