Linear interpolation - Wikipedia
https://en.wikipedia.org/wiki/Linear_interpolationIf the two known points are given by the coordinates and , the linear interpolant is the straight line between these points. For a value x in the interval , the value y along the straight line is given from the equation of slopes which can be derived geometrically from the figure on the right. It is a special case of polynomial interpolation with n = 1.
Chapter 3. Interpolation and Extrapolation
www.it.uom.gr › teaching › linearalgebra3.1 Polynomial Interpolation and Extrapolation Through any two points there is a unique line. Through any three points, a unique quadratic. Et cetera. The interpolating polynomial of degree N − 1 through the N points y1 = f(x1),y2 = f(x2),...,yN = f(xN) is given explicitly by Lagrange’s classical formula, P(x)= (x−x2)(x −x3)...(x −xN) (x1 −x2)(x1 −x3)...