Returns the hyperbolic cosine of a double value.


Numeric cosh()


The hyperbolic cosine of x is defined to be (ex + e-x)/2 where e is Euler's number.

Special cases:

  • If the value is NaN, then the result is NaN.
  • If the value is infinite, then the result is positive infinity.
  • If the value is zero, then the result is 1.0.

The computed result must be within 2.5 ulps of the exact result.