Example 2.  Error Analysis.  Investigate the error for the Newton polynomial approximations in Example 1.

Solution 2 (a).

Investigate the error over the interval  [Graphics:../Images/NewtonPolyMod_gr_231.gif]  for the Newton interpolation polynomial  [Graphics:../Images/NewtonPolyMod_gr_232.gif],  of degree n = 1.

[Graphics:../Images/NewtonPolyMod_gr_233.gif]

[Graphics:../Images/NewtonPolyMod_gr_234.gif]

[Graphics:../Images/NewtonPolyMod_gr_235.gif]
[Graphics:../Images/NewtonPolyMod_gr_236.gif]

[Graphics:../Images/NewtonPolyMod_gr_237.gif]
[Graphics:../Images/NewtonPolyMod_gr_238.gif]
[Graphics:../Images/NewtonPolyMod_gr_239.gif]

[Graphics:../Images/NewtonPolyMod_gr_240.gif]

Use formula(i).    [Graphics:../Images/NewtonPolyMod_gr_241.gif][Graphics:../Images/NewtonPolyMod_gr_242.gif]   is valid for  [Graphics:../Images/NewtonPolyMod_gr_243.gif],  and find the error bound for this example.

[Graphics:../Images/NewtonPolyMod_gr_244.gif]

[Graphics:../Images/NewtonPolyMod_gr_245.gif]

[Graphics:../Images/NewtonPolyMod_gr_246.gif]
[Graphics:../Images/NewtonPolyMod_gr_247.gif]
[Graphics:../Images/NewtonPolyMod_gr_248.gif]
[Graphics:../Images/NewtonPolyMod_gr_249.gif]

[Graphics:../Images/NewtonPolyMod_gr_250.gif]

Thus,  [Graphics:../Images/NewtonPolyMod_gr_251.gif]  is valid for  [Graphics:../Images/NewtonPolyMod_gr_252.gif],  which is a little bit larger than the maximum error  0.00497089.  After all, it is an error bound.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) John H. Mathews 2004