sympy/sympy — pull request #1252 by alxspopov (2012-04-19 23:02:19+00:00)
Title: Added Fresnel integrals into functions/special/error_functions.py

Fresnel sine and cosine integrals were added (`FresnelS` and `FresnelC`).
The asymptotic evaluation, generalised expansion, numerical evaluation and
error function representation was implemented for these classes.

Both with Fresnel cosine integral C(x), Fresnel integrals used in optics,
arise in the description of near field Fresnel diffraction phenomena.
Parametric plot of S(t) against C(t) forms Euler (Cornu) spiral.