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 A198371 #6 Feb 07 2025 16:44:05
%S A198371 1,2,1,5,0,1,2,9,8,4,2,6,4,3,5,2,4,5,7,0,4,8,8,7,1,2,8,4,9,9,1,5,0,2,
%T A198371 5,4,8,7,5,7,7,7,4,5,5,1,7,6,4,2,1,2,8,7,0,7,3,1,8,8,3,5,3,0,9,4,3,4,
%U A198371 5,6,6,3,5,5,5,9,7,9,3,2,3,0,6,9,0,0,6,0,6,1,6,6,4,1,0,2,7,5,2
%N A198371 Decimal expansion of least x having 4*x^2+4x=3*cos(x).
%C A198371 See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e A198371 least x: -1.21501298426435245704887128499150254...
%e A198371 greatest x: 0.460194997750930971424797277964558861...
%t A198371 a = 4; b = 4; c = 3;
%t A198371 f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t A198371 Plot[{f[x], g[x]}, {x, -2, 1}]
%t A198371 r1 = x /. FindRoot[f[x] == g[x], {x, -1.3, -1.2}, WorkingPrecision -> 110]
%t A198371 RealDigits[r1] (* A198371 *)
%t A198371 r2 = x /. FindRoot[f[x] == g[x], {x, .46, .47}, WorkingPrecision -> 110]
%t A198371 RealDigits[r2] (* A198372 *)
%Y A198371 Cf. A197737.
%K A198371 nonn,cons
%O A198371 1,2
%A A198371 _Clark Kimberling_, Oct 24 2011