ABSTRACT
The first-and second-order derivatives of a quadratic Lagrange polynomial are given by Eq. (5.9):
f'ex) ~ P;(x) = 2x - (b + e) f(a) + 2x - (a + e) feb) + 2x - (a + b) f(e) (a - b)(a - e) (b - a)(b - e) (e - a)(e - b)
(5.122a) f"(x) ~ P~(x) = 2f(a) + 2f(b) + 2f(e)
~-b~-~ 0-~0-~ ~-a~-~ (5.122b)
A FORTRAN subroutine, subroutine lagrange, for implementing Eq. (5.122) is presented in Program 5.2.
