Mathematics of Computing -- Numerical Analysis.

This is an easily accessible account of the approximation of functions. It is simple and without unnecessary details, but complete enough to include the classic

This 1987 book examines the approximation of real functions by real rational functions. These are a more convenient tool than polynomials, and interest in them

In Fourier Analysis and Approximation of Functions basics of classical Fourier Analysis are given as well as those of approximation by polynomials, splines and

This is a textbook on classical polynomial and rational approximation theory for the twenty-first century. Aimed at advanced undergraduates and graduate student