Abstract: Let two points a and b located to the right and left of the interval [–1, 1], respectively, be given on the real axis. The extremal problem is stated as follows: find an algebraic polynomial of the n-th degree, whose value is A at point a, it does not exceed M in absolute value in the interval [–1, 1], and takes the largest possible value at point b. This problem is connected with the second Zolotarev problem. A set of values of the parameter A, for which this problem has a unique solution, is indicated in this paper and an alternance characteristic of this solution is given. The behavior of the solution with respect to the parameter A is studied. It is found that the solution can be obtained for certain A using the Chebyshev polynomial, and can be obtained for all other admissible A with the help of the Zolotarev polynomial.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalVestnik St. Petersburg University: Mathematics
Volume53
Issue number1
StatePublished - 26 Mar 2020

    Research areas

  • alternance, Chebyshev polynomials, extremal properties of polynomials, Zolotarev polynomials

    Scopus subject areas

  • Mathematics(all)

ID: 61742161