OFFSET
1,2
COMMENTS
Also decimal expansion of cos(i). - N. J. A. Sloane, Feb 12 2010
cosh(x) = (e^x + e^(-x))/2.
Equals Sum_{n>=0} 1/A010050(n). See Gradsteyn-Ryzhik (0.245.5). - R. J. Mathar, Oct 27 2012
By the Lindemann-Weierstrass theorem, this constant is transcendental. - Charles R Greathouse IV, May 14 2019
REFERENCES
S. Selby, editor, CRC Basic Mathematical Tables, CRC Press, 1970, p. 218.
LINKS
Ivan Panchenko, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Hyperbolic Cosine
Eric Weisstein's World of Mathematics, Hyperbolic Functions
Eric Weisstein's World of Mathematics, Factorial Sums
FORMULA
Continued fraction representation: cosh(1) = 1 + 1/(2 - 2/(13 - 12/(31 - ... - (2*n - 4)*(2*n - 5)/((4*n^2 - 10*n + 7) - ... )))). See A051396 for proof. Cf. A049470 (cos(1)) and A073742 (sinh(1)). - Peter Bala, Sep 05 2016
Equals Product_{k>=0} 1 + 4/((2*k+1)*Pi)^2. - Amiram Eldar, Jul 16 2020
EXAMPLE
1.54308063481524377847790562075...
MAPLE
Digits:=100: evalf(cosh(1)); # Wesley Ivan Hurt, Nov 18 2014
MATHEMATICA
RealDigits[Cosh[1], 10, 120][[1]] (* Harvey P. Dale, Aug 03 2014 *)
PROG
(PARI) cosh(1)
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
Rick L. Shepherd, Aug 07 2002
STATUS
approved