cosh, coshf, coshl - hyperbolic cosine function

Syntax	#include <math.h> double cosh(double x); C11 float coshf(float x); long double coshl(long double x); (End)
Description	These functions compute the hyperbolic cosine of the floating-point number x.
Return val.	cosh(x)	if successful.
	HUGE_VAL HUGE_VALF HUGE_VALL	depending on the function type, if an overflow occurs. errno is set to indicate the error.
Errors	cosh(), coshf() and coshl() will fail if:
	ERANGE	The value of x causes an overflow.
See also	acos(), asin(), atan(), cos(), sinh(), tanh(), math.h.