OFFSET
1,1
COMMENTS
Given on p.3 of Tsironis. The paper has a major typo. Substituting N=3 into equation 16 produces the polynomial 108 - 43x +2x^2 + 2x^3, whose real zero is about -6.0399. The exact value is given in the formula below.
LINKS
G. P. Tsironis, Exact dynamics for fully connected nonlinear networks, arXiv:1101.4721 Jan 25, 2011.
FORMULA
-(1 + f^(1/3)/2^(2/3) + 131/(2f)^(1/3))/3, where f=3307-387*sqrt(43).
EXAMPLE
Chi_c ~ -6.03990424865074743952918719978407940028359436808....
MATHEMATICA
RealDigits[Solve[108 - 43 x + 2 x^2 + 2 x^3 == 0, x][[1, 1, 2]], 10, 150][[1]]
r = (3307 - 387*Sqrt@ 43); RealDigits[-(1 + (r/4)^(1/3) + 131/(2r)^(1/3))/3, 10, 111][[1]] (* Robert G. Wilson v, Jan 31 2011 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Jonathan Vos Post, Jan 27 2011
STATUS
approved