The formula defines the Fresnel cosine
integral C(x) and the Fresnel sine
use a term π t2/2 instead
of t2 in the integral, resulting in a values 2/π times as large.
The Fresnel integral has important applications in the physics of diffraction
and is used in the theory of driving motorcar round a corner quickly.
The curve can be expanded in terms of the spherical
Bessel function of the first kind.