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 A198354 #6 Feb 07 2025 16:44:05
%S A198354 6,5,5,9,9,6,4,2,4,4,5,2,3,9,1,5,4,8,0,7,3,1,0,7,1,3,0,8,6,9,5,9,7,5,
%T A198354 3,4,3,6,2,2,5,1,1,8,1,0,8,9,5,4,2,1,0,3,4,8,3,4,8,2,4,0,6,8,3,3,7,7,
%U A198354 2,5,6,3,0,6,8,6,8,4,6,5,6,9,0,5,6,9,8,8,7,7,5,5,8,7,5,2,2,1,2
%N A198354 Decimal expansion of greatest x having 4*x^2+x=3*cos(x).
%C A198354 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198354 least x: -0.84250907415961557669109359901490911...
%e A198354 greatest x: 0.655996424452391548073107130869590...
%t A198354 a = 4; b = 1; c = 3;
%t A198354 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198354 Plot[{f[x], g[x]}, {x, -1, 1}]
%t A198354 r1 = x /. FindRoot[f[x] == g[x], {x, -.9, -.8}, WorkingPrecision -> 110]
%t A198354 RealDigits[r1] (* A198353 *)
%t A198354 r2 = x /. FindRoot[f[x] == g[x], {x, .65, .66}, WorkingPrecision -> 110]
%t A198354 RealDigits[r2] (* A198354 *)
%Y A198354 Cf. A197737.
%K A198354 nonn,cons
%O A198354 0,1
%A A198354 _Clark Kimberling_, Oct 23 2011