Abstract:
The representation of the derivative of an analytic function as a discrete Fourier transform with a residual term is found using the Cauchy integral formula. The estimation of the residual term is given. An example of joint use of the obtained formula and a standard computer program, in which the algorithm of fast Fourier transform is implemented, for different number of discrete samples is considered.
Keywords:analytic function, higher-order derivative, Cauchy integral formula, discrete Fourier transform, fast Fourier transform, interpolation Lagrange polynomial, residual term of the interpolation formula.