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%I #5 Mar 30 2012 18:57:53
%S 1,6,9,8,9,9,7,7,5,1,9,9,8,4,8,9,0,8,3,1,8,4,2,9,2,8,7,9,6,9,8,5,5,4,
%T 8,1,4,5,6,2,2,3,9,0,8,1,5,2,0,2,2,2,7,3,4,9,7,5,6,9,3,7,1,2,1,9,1,8,
%U 3,3,0,0,6,5,2,0,5,2,6,9,8,0,3,6,9,8,6,8,9,5,3,1,0,1,9,0,4,4,5
%N Decimal expansion of least x having x^2+2x=4*cos(x).
%C See A197737 for a guide to related sequences. The Mathematica program includes a graph.
%e least x: -1.6989977519984890831842928796985548...
%e greatest x: 0.88207436611847498021987395522394374915...
%t a = 1; b = 2; c = 4;
%t f[x_] := a*x^2 + b*x; g[x_] := c*Cos[x]
%t Plot[{f[x], g[x]}, {x, -2, 1}]
%t r1 = x /. FindRoot[f[x] == g[x], {x, -1.7, -1.6}, WorkingPrecision -> 110]
%t RealDigits[r1] (* A197847 *)
%t r2 = x /. FindRoot[f[x] == g[x], {x, .88, .89}, WorkingPrecision -> 110]
%t RealDigits[r2] (* A197848 *)
%Y Cf. A197737.
%K nonn,cons
%O 1,2
%A _Clark Kimberling_, Oct 20 2011
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