Representation by several orthogonal polynomials for sums of finite products of Chebyshev polynomials of the first, third and fourth kinds

Abstract

Abstract The classical linearization problem concerns with determining the coefficients in the expansion of the product of two polynomials in terms of any given sequence of polynomials. As a generalization of this, we consider here sums of finite products of Chebyshev polynomials of the first, third, and fourth kinds, which are different from the ones previously studied. We represent each of them as linear combinations of Hermite, extended Laguerre, Legendre, Gegenbauer, and Jacobi polynomials. Here, the coefficients involve some terminating hypergeometric functions F12 ${}_{2}F_{1}$, F22 ${}_{2}F_{2}$, and F11 ${}_{1}F_{1}$. These representations are obtained by explicit computations.

Keywords

• Sums of finite products
• Chebyshev polynomials
• Hermite polynomial
• Extended Laguerre polynomial
• Legendre polynomial
• Gegenbauer polynomial