# scipy.special.fresnel

scipy.special.fresnel(z, out=None) = <ufunc 'fresnel'>

  Fresnel integrals.

  The Fresnel integrals are defined as

  \[\begin{split}S(z) &= \int_0^z \sin(\pi t^2 /2) dt \\ C(z) &= \int_0^z \cos(\pi t^2 /2) dt.\end{split}\]

  See [dlmf] for details.

  Parameters:
    z array_like

      Real or complex valued argument

    out 2-tuple of ndarrays, optional

      Optional output arrays for the function results

  Returns:
    S, C 2-tuple of scalar or ndarray

      Values of the Fresnel integrals

  See also

  `fresnel_zeros`

    zeros of the Fresnel integrals

  References

  [dlmf]

  NIST Digital Library of Mathematical Functions https://dlmf.nist.gov/7.2#iii

  Examples

      >>> import numpy as np
      >>> import scipy.special as sc

  As z goes to infinity along the real axis, S and C converge to 0.5.

      >>> S, C = sc.fresnel([0.1, 1, 10, 100, np.inf])
      >>> S
      array([0.00052359, 0.43825915, 0.46816998, 0.4968169 , 0.5       ])
      >>> C
      array([0.09999753, 0.7798934 , 0.49989869, 0.4999999 , 0.5       ])

  They are related to the error function `erf`.

      >>> z = np.array([1, 2, 3, 4])
      >>> zeta = 0.5 * np.sqrt(np.pi) * (1 - 1j) * z
      >>> S, C = sc.fresnel(z)
      >>> C + 1j*S
      array([0.7798934 +0.43825915j, 0.48825341+0.34341568j,
             0.60572079+0.496313j  , 0.49842603+0.42051575j])
      >>> 0.5 * (1 + 1j) * sc.erf(zeta)
      array([0.7798934 +0.43825915j, 0.48825341+0.34341568j,
             0.60572079+0.496313j  , 0.49842603+0.42051575j])