### Navigation

- index
- modules |
- next |
- previous |
- NumPy v1.3 Manual (DRAFT) »
- NumPy Reference »
- Routines »
- Mathematical functions »

# numpy.arccosh

`numpy.``arccosh`(x[, out])

  Inverse hyperbolic cosine, elementwise.

  Parameters: | x : array_like Input array.
  Returns: | out : ndarray Array of the same shape and dtype as x.

  Notes

  arccosh is a multivalued function: for each x there are infinitely many numbers z such that cosh(z) = x. The convention is to return the z whose imaginary part lies in [-pi, pi] and the real part in `[0, inf]`.

  For real-valued input data types, arccosh always returns real output. For each value that cannot be expressed as a real number or infinity, it yields `nan` and sets the invalid floating point error flag.

  For complex-valued input, arccosh is a complex analytical function that has a branch cut [-inf, 1] and is continuous from above on it.

  References

  [4] | M. Abramowitz and I.A. Stegun, “Handbook of Mathematical Functions”, 10th printing, 1964, pp. 86. http://www.math.sfu.ca/~cbm/aands/

  [5] | Wikipedia, “Inverse hyperbolic function”, http://en.wikipedia.org/wiki/Arccosh

  Examples

      >>> np.arccosh([np.e, 10.0])
      array([ 1.65745445,  2.99322285])

### Navigation

- index
- modules |
- next |
- previous |
- NumPy v1.3 Manual (DRAFT) »
- NumPy Reference »
- Routines »
- Mathematical functions »