OFFSET
1,3
COMMENTS
Gamma(1) = Gamma(2) = 1, and the interval (1,2) gives the portion of the graph of y = Gamma x that lies under the line y = 1, as shown by the Mathematica program.
MATHEMATICA
r = NIntegrate[Sqrt[1 + D[Gamma[x], x]^2], {x, 1, 2}, WorkingPrecision -> 200]
RealDigits[r][[1]]
Plot[Gamma[x] - 1, {x, .5, 2.5}]
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Clark Kimberling, Jul 03 2020
STATUS
approved