OFFSET
0,1
EXAMPLE
u = 0.763926663317091041161960918884092435074956...
MATHEMATICA
x = x /.FindRoot[1/2 x Sqrt[1 + 4 x^2] + 1/4 ArcSinh[2 x] == 1, {x, 0}, WorkingPrecision -> 200]
RealDigits[x][[1]]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Jul 04 2020
STATUS
approved