Darboux's formula


In mathematical analysis, Darboux's formula is a formula introduced by for summing infinite series by using integrals or evaluating integrals using infinite series. It is a generalization to the complex plane of the Euler–Maclaurin summation formula, which is used for similar purposes and derived in a similar manner. Darboux's formula can also be used to derive the Taylor series from calculus.

Statement

If φ is a polynomial of degree n and f an analytic function then
The formula can be proved by repeated integration by parts.

Special cases

Taking φ to be a Bernoulli polynomial in Darboux's formula gives the Euler–Maclaurin summation formula. Taking φ to be n gives the formula for a Taylor series.