In mathematics, the integral of a function of several variables
defined on a line or curve that has been expressed in terms of
arc length (see length of a curve). An ordinary definite
integral is defined over a line segment, whereas a line integral
may use a more general path, such as a parabola or a circle.
Line integrals are used extensively in the theory of functions
of a complex variable. Learn more about line integral with a
free trial on Britannica.com. The COmet Nucleus TOUR (CONTOUR)
was a NASA Discovery-class space probe that failed shortly after
launch. It had as its primary objective close flybys of two
comet nuclei with the possibility of a flyby of a third known
comet or an as-yet-undiscovered comet. The two comets scheduled
to be visited were Encke and Schwassmann-Wachmann-3, and the
third target was d'Arrest. It was hoped that a new comet would
have been discovered that would have been in the inner solar
system between 2006 and 2008, in which case the spacecraft
trajectory would have been chang