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# numpy.tanh

`numpy.``tanh`(x[, out]) = <ufunc 'tanh'>

  Compute hyperbolic tangent element-wise.

  Equivalent to `np.sinh(x)/np.cosh(x)` or `-1j * np.tan(1j*x)`.

  Parameters: | x : array_like Input array. out : ndarray, optional Output array of same shape as x.
  Returns: | y : ndarray The corresponding hyperbolic tangent values.
  Raises: | ValueError: invalid return array shape : if out is provided and out.shape != x.shape (See Examples)

  Notes

  If out is provided, the function writes the result into it, and returns a reference to out. (See Examples)

  References

  [R248] | M. Abramowitz and I. A. Stegun, Handbook of Mathematical Functions. New York, NY: Dover, 1972, pg. 83. http://www.math.sfu.ca/~cbm/aands/

  [R249] | Wikipedia, “Hyperbolic function”, http://en.wikipedia.org/wiki/Hyperbolic_function

  Examples

      >>> np.tanh((0, np.pi*1j, np.pi*1j/2))
      array([ 0. +0.00000000e+00j,  0. -1.22460635e-16j,  0. +1.63317787e+16j])

      >>> # Example of providing the optional output parameter illustrating
      >>> # that what is returned is a reference to said parameter
      >>> out2 = np.tanh([0.1], out1)
      >>> out2 is out1
      True

      >>> # Example of ValueError due to provision of shape mis-matched `out`
      >>> np.tanh(np.zeros((3,3)),np.zeros((2,2)))
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
      ValueError: invalid return array shape