Chapter 3 Interpolation and polynomial Approximation
Chapter 3 Interpolation and polynomial Approximation
The Taylor polynomial p(x 1+x+0.5x which approximates f(x)=e"over(-1, 11 15 p(x) 0.5 -08-06-04-02 04 0.6 08
The Chebyshev approximation q(x=1+1.129772X+0. 532042x for f(x=e over[-1, 1]1 25 15 y=q(x) 05 08-06-04-02 06
The graph of the collocation polynomial that passes through(1, 2), (2, 1),(3, 5), (4, 6), and(5. 1) 15 35 re 1.3
Table 1.1 Taylor Series Expansions for Some Common Functions Sin( r= ′×25 + or all r 4x6 cos(a=1 + TOr 4!6 e=1+x+-+++ 3!4 n(1+x)=x C乙 3 + 1<x<1 234 arctan(a)=a + 1<x<1 35 +x)2=1+mD-1)2 +… for ac|<1
Table 1.2 Partial sums s used to determine e Sn=1+++…+ n0123456789 2.0 2.5 2.666666666666 2.708333. 2.716666666666 2.718805555555 2.718253968254 2.718278769841 2.718281525573 2.718281801146. 2.718281826199 12 2.718281828286 13 2.718281828447. 14 2.718281828458.. 15 2.718281828459
Theorem 1. 1(Taylor Polynomial Approximation). Assume that f E CN+ a, b ando∈[a, is a fixed value.fr∈[a,],then f(a)=PN(a)+ en(c), where PN(a)is a polynomial that can be used to approximate f(ar) f()≈()=∑ N f()(ro) k! -0 (1.2) The error term EN(a) has the form (N+1 EN(a) (N+1)! for some value c=c(a) that lies between r and To