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%I #13 Oct 17 2021 11:33:37
%S 7,8,5,4,7,5,7,4,3,8,2,3,7,6,1,2,5,6,4,8,6,1,0,0,8,5,8,2,7,6,4,5,7,0,
%T 4,5,7,8,4,8,5,4,1,9,2,9,2,3,0,0,4,6,6,9,4,4,2,3,2,8,1,4,4,8,8,2,6,5,
%U 6,1,4,2,1,4,0,8,6,5,3,5,2,8,2,3,4,9,8,6,6,7,8,9,3,9,9,9,8,0,0,5,3,6,2,1,3
%N Decimal expansion of third solution of equation cos(x)*cosh(x) = -1.
%C This is an equation related to a cantilever beam: cos(x)*cosh(x) = -1. The first three solutions are: 1.875 (A076417), 4.69409 (A076418) and 7.854757 (this sequence).
%H Z. Guede, I. Elishakov, <a href="http://dx.doi.org/10.1016/S0960-0779(00)00014-X">A fifth-order polynomial that serves as both buckling and vibration mode of an inhomogeneous structure</a>, Chaos, Solitons and Fractals 12 (7) (2001) 1267-1298.
%e cos(x) cosh(x) = -1, x = 7.854757...
%t RealDigits[x/.FindRoot[Cos[x]Cosh[x]==-1,{x,8},WorkingPrecision-> 120]] [[1]] (* _Harvey P. Dale_, Oct 17 2021 *)
%o (PARI) solve(x=7, 8, cos(x)*cosh(x) + 1) \\ _Michel Marcus_, Sep 11 2019
%Y Cf. A076417, A076418.
%K easy,nonn,cons
%O 1,1
%A _Zak Seidov_, Oct 10 2002
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