 We can write

where formula_34 is the coefficient of formula_35 in formula_31.Taking the limit of to formula_37 yields using L'Hôpital's rule

We can thus write the integral expression for the weights as

In the integrand, writing

yields

provided formula_41, because

is a polynomial of degree which is then orthogonal to formula_31.So, if is a polynomial of at most nth degree we have

We can evaluate the integral on the right hand side for formula_45 as follows.