TY - JOUR T1 - Formulas of Numerical Differentiation on a Uniform Mesh for Functions with the Exponential Boundary Layer AU - Zadorin , Alexander AU - Tikhovskaya , Svetlana JO - International Journal of Numerical Analysis and Modeling VL - 4 SP - 590 EP - 608 PY - 2019 DA - 2019/02 SN - 16 DO - http://doi.org/ UR - https://global-sci.org/intro/article_detail/ijnam/13016.html KW - Function of one variable, exponential boundary layer, formulas of numerical differentiation, an error estimate. AB -

It is known that the solution of a singularly perturbed problem corresponds to the function with large gradients in a boundary layer. The application of Lagrange polynomial on a uniform mesh to interpolate such functions leads to large errors. To achieve the error estimates uniform with respect to a small parameter, we can use either a polynomial interpolation on a mesh which condenses in a boundary layer or we can use special interpolation formulas which are exact on a boundary layer component of the interpolating function. In this paper, we construct and study the formulas of numerical differentiation based on the interpolation formulas which are exact on a boundary layer component. We obtained the error estimates which are uniform with respect to a small parameter. Some numerical results validating the theoretical estimates are discussed.