3.1 The Interpolating Polynomial（站点）

Cubic Interpolation：                               https://www.youtube.com/watch?

v=EtzlEA9MIwI

Quadratic Spline Interpolation               https://www.youtube.com/watch?

v=j_jBK7zJ1vU

Lagrange Interpolating Polynomials:  https://www.youtube.com/watch?v=vAgKE5wvR4Y

Vandermonde matrix:                             https://www.youtube.com/watch?v=rYekrCcRcGk