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Decimal expansion of x>0 satisfying 2*x^2-4*cos(x)=-1.
2

%I #5 Mar 30 2012 18:57:56

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

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

%U 5,6,1,6,6,9,7,8,9,9,2,1,2,1,5,9,3,5,4,2,3,9,7,7,6,9,9,5,7,3,4

%N Decimal expansion of x>0 satisfying 2*x^2-4*cos(x)=-1.

%C See A198755 for a guide to related sequences. The Mathematica program includes a graph.

%e x=0.8799704032423942387963153440536443839...

%t a = 2; b = -4; c = -1;

%t f[x_] := a*x^2 + b*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, .87, .88}, WorkingPrecision -> 110]

%t RealDigits[r] (* A198884 *)

%Y Cf. A198755.

%K nonn,cons

%O 0,1

%A _Clark Kimberling_, Oct 31 2011