Common Points Between Perturbed Chebyshev Polynomials of Second Kind

We consider some perturbation of the Chebyshev polynomials of second kind obtained by modifying one of its recurrence coefficients at an arbitrary order. The goal of this work is to point out that perturbed Chebyshev polynomials of fixed degree and different values of parameters of perturbation have some common points that are zeros of two Chebyshev polynomials of second kind of lower degrees. These common points can be simple or double. We identify the cases in which they are common zeros.