Approximation Properties of Sums of the Form $\sum_k\lambda_kh(\lambda_k z)$

A method for approximating functions $f$ analytic in a neighborhood of the point $z=0$ by finite sums of the form $\sum_k\lambda_kh(\lambda_k z)$ is proposed, where $h$ is a chosen function analytic on the unit disk and the approximation is carried out by choosing the complex numbers $\lambda_k=\lambda_k(f)$. Some applications to numerical analysis are given.