What is the term for this family of improper integrals?

291 Views Asked by At

What is the name of the integrals of this form?

$$\int_{0}^{\infty} \frac{\sin\left(\frac{x}{1}\right)\sin\left(\frac{x}{3}\right)\cdots\sin\left(\frac{x}{2n + 1}\right)}{\left(\frac{x}{1}\right)\left(\frac{x}{3}\right)\cdots\left(\frac{x}{2n + 1}\right)} \:dx$$

1

There are 1 best solutions below

2
On BEST ANSWER

These are examples of Borwein integrals. See:

Borwein, D.; Borwein, J.M., "Some Remarkable Properties of $\operatorname{Sinc}$ and Related Integrals", Ramanujan J. 5 (2001), 73-89.

John Baez' Azimuth blog has an illuminating post discussing these integrals, and Greg Egan gave an intuitive explanation in terms of Fourier transforms for the pattern-breaking phenomenon often mentioned when these integrals come up.