Lp, approximation by analytic functions

Approximation of Analytic Functions by Chebyshev Functions

and Applied Analysis 3 where we refer to 1.4 for the am’s and we follow the convention ∏m−1 j m · · · 1. We can easily check that cm’s satisfy the following relation: m 2 m 1 cm 2 − ( m2 − n2 ) cm am 2.2 for any m ∈ {0, 1, 2, . . .}. Theorem 2.1. Assume that n is a positive integer and the radius of convergence of the power series ∑∞ m 0 amx m is ρ > 0. Let ρ0 min{1, ρ}. Then, every solution y ...

Approximation of Analytic Functions by Special Functions

We survey the recent results concerning the applications of power series method to the study of Hyers–Ulam stability of differential equations.

Approximation of Analytic Functions by Kummer Functions

Approximation of Analytic Functions by Bessel’s Functions of Fractional Order

and Applied Analysis 3 The convergence of the power series ∑∞ m 0 amx m seems not to guarantee the existence of solutions to the inhomogeneous Bessel differential equation 1.4 . Thus, we adopt an additional condition to ensure the existence of solutions to the equation. Theorem 2.1. Let ν be a positive nonintegral number, and let ρ be a positive constant. Assume that the radius of convergence o...

On Approximation to Analytic Functions by Rational Functions

Let f(z) be analytic in the interior of a rectifiable Jordan curve C and continuous in the corresponding closed region C. The relation between continuity properties of f(z) on C and degree of approximarion to f(z) by polynomials irn(z) in z of respective degrees n, n = 1, 2, • • • , has been extensively studied. In the present paper we study the relation between continuity properties of f(z) on...