Numerical Analysis, Numerical Integration.
3 due to the property of the Legendre orthogonal polynomials. Since we have divided a polynomial of degree ≤ 2n+1 denoted as f(x), by a polynomial of degree n+1, denoted as L(x), then the terms Q(x) and R(x) will be polynomials of degree ≤ n. The properties of Legendre Polynomials make it so that