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# numpy.tan

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

  Compute tangent element-wise.

  Equivalent to `np.sin(x)/np.cos(x)` element-wise.

  Parameters: | x : array_like Input array. out : ndarray, optional Output array of same shape as x.
  Returns: | y : ndarray The corresponding 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

  M. Abramowitz and I. A. Stegun, Handbook of Mathematical Functions. New York, NY: Dover, 1972.

  Examples

      >>> from math import pi
      >>> np.tan(np.array([-pi,pi/2,pi]))
      array([  1.22460635e-16,   1.63317787e+16,  -1.22460635e-16])
      >>>
      >>> # Example of providing the optional output parameter illustrating
      >>> # that what is returned is a reference to said parameter
      >>> out2 = np.cos([0.1], out1)
      >>> out2 is out1
      True
      >>>
      >>> # Example of ValueError due to provision of shape mis-matched `out`
      >>> np.cos(np.zeros((3,3)),np.zeros((2,2)))
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
      ValueError: invalid return array shape