Math 495B Polynomial Interpolation Special case of a step function. Frederic Gibou
What is polynomial interpolation? -Linear interpolation (An intuitive approach) -Higher order polynomial interpolation (second order) How to choose the nodes. -Case of a smooth function (Straight forward) -Case of a step function (Decision to choose the nodes).
Intuitive approach
Higher Order interpolation Curve to be approximated
Linear interpolation Higher Order interpolation Curve to be approximated
Linear interpolation Higher Order interpolation Curve to be approximated
Linear interpolation Higher Order interpolation Curve to be approximated
Linear interpolation Quadratic interpolation Higher Order interpolation Curve to be approximated
Linear interpolation Quadratic interpolation Higher Order interpolation Curve to be approximated
Higher Order interpolation Interpolation with a polynomial of degree 2
Impose: Higher Order interpolation
Solve for the coefficients:
Moral : Need 3 points to get a polynomial interpolation of degree 2. Higher Order interpolation
§How to choose the points? Case of a smooth function. –3 consecutive points.
Case of a step function Curve to be approximated
Linear interpolation Case of a step function Curve to be approximated
Linear interpolation Quadratic interpolation Case of a step function Curve to be approximated
Linear interpolation Quadratic interpolation Case of a step function Curve to be approximated
Linear interpolation Quadratic interpolation Case of a step function Curve to be approximated
Linear interpolation Quadratic interpolation Gibbs phenomenon Case of a step function Curve to be approximated
Case of a step function Curve to be approximated
Case of a step function Curve to be approximated Linear
Case of a step function Curve to be approximated
Case of a step function Curve to be approximated
Case of a step function Curve to be approximated
Case of a step function Curve to be approximated
Quadratic interpolation Case of a step function Curve to be approximated