An Error Estimate for Gauss-Jacobi Quadrature Formula with the Hermite Weight W(x)=exp(-x2)
The main result says in particular that if is a trigonometric polynomial of degree n having all its zeros in the open upper half-plane such that |t(ξ)| ≥ μ on the real axis and cₙ ≠ 0, then |t’(ξ)| ≥ μn for all real ξ.