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 A198367 #6 Feb 07 2025 16:44:05
%S A198367 1,1,2,8,8,6,4,4,2,0,5,2,3,9,8,6,1,3,9,4,7,7,0,0,4,6,6,3,0,6,1,8,8,9,
%T A198367 5,7,3,6,9,5,9,7,3,2,4,1,1,0,7,6,5,2,1,7,0,0,9,7,5,6,1,3,7,9,9,7,7,1,
%U A198367 6,8,9,1,6,9,3,8,1,2,9,9,6,0,9,6,8,4,1,0,2,9,1,6,3,7,6,9,9,7,7
%N A198367 Decimal expansion of least x having 4*x^2+3x=4*cos(x).
%C A198367 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198367 least x: -1.128864420523986139477004663061889573...
%e A198367 greatest x: 0.6060777836486264536657977579905629...
%t A198367 a = 4; b = 3; c = 4;
%t A198367 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198367 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198367 r1 = x /. FindRoot[f[x] == g[x], {x, -1.2, -1.1}, WorkingPrecision -> 110]
%t A198367 RealDigits[r1] (* A198367 *)
%t A198367 r2 = x /. FindRoot[f[x] == g[x], {x, .60, .61}, WorkingPrecision -> 110]
%t A198367 RealDigits[r2] (* A198368 *)
%Y A198367 Cf. A197737.
%K A198367 nonn,cons
%O A198367 1,3
%A A198367 _Clark Kimberling_, Oct 24 2011