3.5.1.3.35 Fresnel_s

Definition:

$S = fresnel\_s(x)$ evaluates an approximation to the Fresnel Integral

$S(x)=\int_0^x\sin (\frac \pi 2t^2)dt$

The function is based on Chebyshev expansions.

For more information please review the s20acc function in the NAG document.

Parameters:

x (input, double)
The argument x of the function.
s (output, double)
Approximation of the Fresnel Integral.