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Decimal expansion of x > 0 satisfying 2*x^2 + x*cos(x) = 3.
3

%I #10 Aug 03 2021 14:28:18

%S 1,1,2,0,8,2,7,8,9,9,0,7,2,4,6,4,1,0,5,0,1,0,8,0,2,6,5,5,1,2,3,8,2,4,

%T 4,1,4,8,4,1,5,4,0,8,0,2,6,3,1,7,7,8,5,0,7,9,0,8,7,2,0,2,4,4,4,0,8,1,

%U 6,1,3,3,0,6,8,0,5,0,0,7,0,6,7,6,8,3,8,6,5,7,0,5,7,9,1,6,6,0,3

%N Decimal expansion of x > 0 satisfying 2*x^2 + x*cos(x) = 3.

%C See A199170 for a guide to related sequences. The Mathematica program includes a graph.

%e negative: -1.29477176551027054190068103147021856144266...

%e positive: 1.120827899072464105010802655123824414841540...

%t a = 2; b = 1; c = 3;

%t f[x_] := a*x^2 + b*x*Cos[x]; g[x_] := c

%t Plot[{f[x], g[x]}, {x, -2, 2}, {AxesOrigin -> {0, 0}}]

%t r = x /. FindRoot[f[x] == g[x], {x, -1.3, -1.2}, WorkingPrecision -> 110]

%t RealDigits[r] (* A199267 *)

%t r = x /. FindRoot[f[x] == g[x], {x, 1.12, 1.13}, WorkingPrecision -> 110]

%t RealDigits[r] (* A199268 *)

%Y Cf. A199170, A199267.

%K nonn,cons

%O 1,3

%A _Clark Kimberling_, Nov 04 2011

%E a(89) onwards corrected by _Georg Fischer_, Aug 03 2021