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Math 6610 • Analysis of Numerical Methods I

Fall 1999 • Question 1

Quadrature Consider the quadrature formula \[ \int _a^b w(x)f(x)\,dx=\sum _{i=0}^n \alpha _i f(\xi _i)+E. \tag {1} \] \(w\) is a given positive weight function. The knots \(\xi _i\) and the weights \(\alpha _i\) are at your disposal. How do you choose them so that the error \(E\) is 0 for all polynomials \(f\) of degree as high as possible? How high is possible? Give reasons for your answers.

Raw LaTeX

{Quadrature}
Consider the quadrature formula
\[
  \int_a^b w(x)f(x)\,dx=\sum_{i=0}^n \alpha_i f(\xi_i)+E. \tag{1}
\]
\(w\) is a given positive weight function. The knots \(\xi_i\) and the weights
\(\alpha_i\) are at your disposal. How do you choose them so that the error \(E\) is 0
for all polynomials \(f\) of degree as high as possible? How high is possible? Give
reasons for your answers.