In this paper, two parametric families of functions, the so-called Complementary Fresnel
Integral and the Lommel type, which are of generalized Fresnel integral type, are considered.
We review the problems of existence and uniqueness of their zeros in certain determined
intervals, called location intervals, which improve previous results of other authors. For the
approximation error obtained, bounds, monotonicity as well as the asymptotic behavior are
analyzed. The study uses results from the theory of ?xed point of real functions, introducing
the concept of ??xed point sequential problem? (FPSP) and the properties of certain special