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A354684
Decimal expansion of the horizontal distance between the equal-height endpoints of a suspended unit-length chain for which the area between the chord joining the endpoints and the chain has a maximum value.
1
6, 7, 1, 6, 2, 8, 5, 3, 0, 5, 9, 0, 0, 5, 9, 6, 3, 0, 1, 7, 7, 0, 1, 1, 2, 1, 8, 8, 9, 6, 7, 6, 2, 4, 2, 4, 1, 5, 9, 8, 0, 6, 0, 2, 5, 0, 7, 0, 6, 7, 3, 3, 4, 0, 4, 4, 5, 4, 8, 3, 6, 3, 7, 8, 7, 8, 1, 5, 9, 0, 6, 6, 1, 6, 1, 0, 8, 1, 0, 2, 0, 7, 9, 5, 8, 6, 6, 0, 7, 1, 7, 8, 6, 9, 2, 3, 5, 1, 8, 5, 7, 8, 8, 0, 1
OFFSET
0,1
COMMENTS
The maximum area is x*/(2*(x^2 + 2)) = 0.154908..., where x is given in the Formula section.
LINKS
Amiram Eldar, Illustration.
Murray S. Klamkin, Problem E 1199, The American Mathematical Monthly, Vol. 63, No. 1 (1956), p. 39; Maximum Area Between a Hanging Chain and Its Chord, Solution to Problem E 1199 by C. M. Sandwick, Sr., ibid., Vol. 63, No. 7 (1956), pp. 495-496.
Wikipedia, Catenary.
FORMULA
Equals arcsinh(x)/x where x = 2.391374... is the positive root of the equation arcsinh(x)/x = 2*sqrt(x^2+1)/(x^2+2).
EXAMPLE
0.67162853059005963017701121889676242415980602507067...
MATHEMATICA
xmax = x /. FindRoot[ArcSinh[x]/x == 2*Sqrt[x^2 + 1]/(x^2 + 2), {x, 2}, WorkingPrecision -> 120]; RealDigits[ArcSinh[xmax]/xmax][[1]]
CROSSREFS
Cf. A225146.
Sequence in context: A011483 A319458 A296459 * A308915 A294644 A256128
KEYWORD
nonn,cons
AUTHOR
Amiram Eldar, Jun 03 2022
STATUS
approved