OFFSET
0,1
EXAMPLE
u = 0.5897552158402901575359617596...
MATHEMATICA
u = u /. FindRoot[-Sqrt[2] + Sqrt[1 + E^(2 u)] + ArcTanh[Sqrt[2]] -
ArcTanh[Sqrt[1 + E^(2 u)]] - 1, {u, 0}, WorkingPrecision -> 100]
RealDigits[u][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Jul 06 2020
STATUS
approved