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A recovery of Brouncker's proof for the quadrature continued fraction.

Sergey Khrushchev (2006)

Publicacions Matemàtiques

350 years ago in Spring of 1655 Sir William Brouncker on a request by John Wallis obtained a beautiful continued fraction for 4/π. Brouncker never published his proof. Many sources on the history of Mathematics claim that this proof was lost forever. In this paper we recover the original proof from Wallis' remarks presented in his Arithmetica Infinitorum. We show that Brouncker's and Wallis' formulas can be extended to MacLaurin's sinusoidal spirals via related Euler's products. We derive Ramanujan's...

An integral transform and its application in the propagation of Lorentz-Gaussian beams

A. Belafhal, E.M. El Halba, T. Usman (2021)

Communications in Mathematics

The aim of the present note is to derive an integral transform I = 0 x s + 1 e - β x 2 + γ x M k , ν 2 ζ x 2 J μ ( χ x ) d x , involving the product of the Whittaker function M k , ν and the Bessel function of the first kind J μ of order μ . As a by-product, we also derive certain new integral transforms as particular cases for some special values of the parameters k and ν of the Whittaker function. Eventually, we show the application of the integral in the propagation of hollow higher-order circular Lorentz-cosh-Gaussian beams through an ABCD optical system (see,...

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