1,1

This is an equation related to a cantilever beam: cos(x)*cosh(x) = -1. The first three solutions are: 1.875 (A076417), 4.69409 (this sequence) and 7.854757 (A076419).

Table of n, a(n) for n=1..105.

Z. Guede, I. Elishakov, A fifth-order polynomial that serves as both buckling and vibration mode of an inhomogeneous structure, Chaos, Solitons and Fractals 12 (7) (2001) 1267-1298.

4.694091132974174576436391778...

RealDigits[x/.FindRoot[Cos[x]Cosh[x]==-1, {x, 4}, WorkingPrecision-> 120]] [[1]] (* Harvey P. Dale, May 01 2019 *)

(PARI) solve(x=4, 5, cos(x)*cosh(x) + 1) \\ Michel Marcus, Sep 11 2019

Cf. A076417, A076419.

Sequence in context: A210616 A238167 A307036 * A059910 A019837 A132160

Adjacent sequences: A076415 A076416 A076417 * A076419 A076420 A076421

easy,nonn,cons

Zak Seidov, Oct 10 2002

approved