Approximation of second and third order derivatives by Fourier coefficients

Title	Approximation of second and third order derivatives by Fourier coefficients
Authors	N. D. Kuzmichev¹ ¹National Research Mordovian State University
Annotation	The proof of the theorems is given, according to which the second and other higher derivatives of a function belonging to the Helder-Lipschitz class C^(G) can be approximated with any predetermined accuracy by a finite sum of the Fourier coefficients of the function for a harmonically modulated argument.
Keywords	Gelder-Lipschitz lass, function, second, third and higher derivatives of a function, Fourier coefficient dependencies, approximation, harmonically modulated argument.
Citation	Kuzmichev N. D. ''Approximation of second and third order derivatives by Fourier coefficients'' [Electronic resource]. Mathematical modeling, numerical methods, and software systems: Collection of materials from the 12th All‑Russian Scientific Youth School‑Seminar named after E. V. Voskresensky (Saransk, July 21–24, 2026). - pp. 115-120. Available at: https://conf.svmo.ru/files/2026/papers/paper86.pdf. - Date of access: 25.09.2026.