COSH(3) Linux Programmer's Manual COSH(3)
cosh - hyperbolic cosine function
#include <math.h> double cosh(double x);
The cosh() function returns the hyperbolic cosine of x, which is defined mathematically as (exp(x) + exp(-x)) / 2.
SVID 3, POSIX, BSD 4.3, ISO 9899
acosh(3), asinh(3), atanh(3), sinh(3), tanh(3) June 13, 1993 1