OFFSET
0,1
COMMENTS
Inverse of A248617.
This is the angle of the unique wedge having its apex at the origin and kissing the exponential curve y=exp(x) on one side, and its inverse logarithmic function y=log(x) on the other side. - Stanislav Sykora, May 31 2015
LINKS
Stanislav Sykora, Table of n, a(n) for n = 0..2000
Wikipedia, Gudermannian function.
FORMULA
Equals arcsin((exp(2)-1)/(exp(2)+1)). - Vaclav Kotesovec, Oct 11 2014
From Amiram Eldar, Apr 07 2022: (Start)
Equals 2*arctan(tanh(1/2)).
Equals Integral_{x=0..1} sech(x) dx. (End)
EXAMPLE
0.86576948323965862428960184619184444137967919924876009961184822974244822945841...
The wedge angle in degrees:
49.6049374208547003776513077348112118247866748819092710723979907940346891648208... - Stanislav Sykora, May 31 2015
MAPLE
evalf(arcsin((exp(2)-1)/(exp(2)+1)), 100) # Vaclav Kotesovec, Oct 11 2014
MATHEMATICA
RealDigits[ Gudermannian[ 1], 10, 111][[1]]
PROG
(PARI) asin((exp(2)-1)/(exp(2)+1)) \\ Michel Marcus, Oct 11 2014
(PARI) atan(exp(1))-atan(1/exp(1)) \\ Stanislav Sykora, May 31 2015
(PARI) 2*atan(exp(1))-Pi/2 \\ Charles R Greathouse IV, Jun 02 2015
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Robert G. Wilson v, Oct 09 2014
STATUS
approved