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

Solution 2 (b).

Investigate the error over the interval  [Graphics:../Images/NewtonPolyMod_gr_253.gif]  for the Newton interpolation polynomial  [Graphics:../Images/NewtonPolyMod_gr_254.gif],  of degree n = 2.

[Graphics:../Images/NewtonPolyMod_gr_255.gif]

[Graphics:../Images/NewtonPolyMod_gr_256.gif]

[Graphics:../Images/NewtonPolyMod_gr_257.gif]
[Graphics:../Images/NewtonPolyMod_gr_258.gif]

[Graphics:../Images/NewtonPolyMod_gr_259.gif]
[Graphics:../Images/NewtonPolyMod_gr_260.gif]
[Graphics:../Images/NewtonPolyMod_gr_261.gif]

[Graphics:../Images/NewtonPolyMod_gr_262.gif]

Use formula (ii).    [Graphics:../Images/NewtonPolyMod_gr_263.gif][Graphics:../Images/NewtonPolyMod_gr_264.gif]   is valid for  [Graphics:../Images/NewtonPolyMod_gr_265.gif],  and find the error bound for this example.

[Graphics:../Images/NewtonPolyMod_gr_266.gif]

[Graphics:../Images/NewtonPolyMod_gr_267.gif]

[Graphics:../Images/NewtonPolyMod_gr_268.gif]
[Graphics:../Images/NewtonPolyMod_gr_269.gif]
[Graphics:../Images/NewtonPolyMod_gr_270.gif]
[Graphics:../Images/NewtonPolyMod_gr_271.gif]

[Graphics:../Images/NewtonPolyMod_gr_272.gif]

Thus,  [Graphics:../Images/NewtonPolyMod_gr_273.gif]  is valid for  [Graphics:../Images/NewtonPolyMod_gr_274.gif],  which is a little bit larger than the maximum error  0.000116469.  After all, it is an error bound.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) John H. Mathews 2004