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 A196819 Decimal expansion of the least x>0 satisfying 1/(1+x^2)=4*cos(x). 6

%I

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

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

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

%N Decimal expansion of the least x>0 satisfying 1/(1+x^2)=4*cos(x).

%e x=1.4933195357382420192666761841798184096253499369741587866...

%t Plot[{1/(1 + x^2), Cos[x], 2 Cos[x], 3 Cos[x], 4 Cos[x]}, {x, 0, 2}]

%t t = x /. FindRoot[1 == (1 + x^2) Cos[x], {x, 1, 1.5}, WorkingPrecision -> 100]

%t RealDigits[t] (* A196816 *)

%t t = x /. FindRoot[1 == 2 (1 + x^2) Cos[x], {x, 1, 1.6},

%t WorkingPrecision -> 100]

%t RealDigits[t] (* A196817 *)

%t t = x /. FindRoot[1 == 3 (1 + x^2) Cos[x], {x, 1, 1.6},

%t WorkingPrecision -> 100]

%t RealDigits[t] (* A196818 *)

%t t = x /. FindRoot[1 == 4 (1 + x^2) Cos[x], {x, 1, 1.6},

%t WorkingPrecision -> 100]

%t RealDigits[t] (* A196819 *)

%t t = x /. FindRoot[1 == 5 (1 + x^2) Cos[x], {x, 1, 1.6},

%t WorkingPrecision -> 100]

%t RealDigits[t] (* A196820 *)

%t t = x /. FindRoot[1 == 6 (1 + x^2) Cos[x], {x, 1, 1.6},

%t WorkingPrecision -> 100]

%t RealDigits[t] (* A196821 *)

%Y Cf. A196914.

%K nonn,cons

%O 1,2

%A _Clark Kimberling_, Oct 06 2011

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Last modified July 18 11:39 EDT 2019. Contains 325139 sequences. (Running on oeis4.)