# Function G2lib::FresnelCS(real_type, real_type&, real_type&)

- Defined in File Fresnel.cc

## Function Documentation

void G2lib::FresnelCS(real_type x, real_type &C, real_type &S)

  Purpose:

  Compute Fresnel integrals C(x) and S(x)

  \[ S(x) = \int_0^x \sin t^2 \,\mathrm{d} t, \qquad C(x) = \int_0^x \cos t^2 \,\mathrm{d} t \]

  Example:

  \( x \) | \( C(x) \) | \( S(x) \)
  --- | --- | ---
  0.0 | 0.00000000 | 0.00000000
  0.5 | 0.49234423 | 0.06473243
  1.0 | 0.77989340 | 0.43825915
  1.5 | 0.44526118 | 0.69750496
  2.0 | 0.48825341 | 0.34341568
  2.5 | 0.45741301 | 0.61918176

  Adapted from:

  - William J. Thompson, Atlas for computing mathematical functions : an illustrated guide for practitioners, with programs in C and Mathematica, Wiley, 1997.

  Author:

  - Venkata Sivakanth Telasula, email:
    , date: August 11, 2005

  Parameters

    - y – [in] Argument of \( C(y) \) and \( S(y) \)

    - C – [out] \( C(x) \)

    - S – [out] \( S(x) \)