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

Solution 2 (c).

Investigate the error over the interval  [Graphics:../Images/NewtonPolyMod_gr_275.gif]  for the Newton interpolation polynomial  [Graphics:../Images/NewtonPolyMod_gr_276.gif],  of degree n = 3.

[Graphics:../Images/NewtonPolyMod_gr_277.gif]

[Graphics:../Images/NewtonPolyMod_gr_278.gif]

[Graphics:../Images/NewtonPolyMod_gr_279.gif]
[Graphics:../Images/NewtonPolyMod_gr_280.gif]

[Graphics:../Images/NewtonPolyMod_gr_281.gif]
[Graphics:../Images/NewtonPolyMod_gr_282.gif]
[Graphics:../Images/NewtonPolyMod_gr_283.gif]

[Graphics:../Images/NewtonPolyMod_gr_284.gif]

Use formula (iii).    [Graphics:../Images/NewtonPolyMod_gr_285.gif][Graphics:../Images/NewtonPolyMod_gr_286.gif]   is valid for  [Graphics:../Images/NewtonPolyMod_gr_287.gif],  and find the error bound for this example.  

[Graphics:../Images/NewtonPolyMod_gr_288.gif]

[Graphics:../Images/NewtonPolyMod_gr_289.gif]

[Graphics:../Images/NewtonPolyMod_gr_290.gif]
[Graphics:../Images/NewtonPolyMod_gr_291.gif]
[Graphics:../Images/NewtonPolyMod_gr_292.gif]
[Graphics:../Images/NewtonPolyMod_gr_293.gif]

[Graphics:../Images/NewtonPolyMod_gr_294.gif]

Thus,  [Graphics:../Images/NewtonPolyMod_gr_295.gif]   is valid for  [Graphics:../Images/NewtonPolyMod_gr_296.gif],  which is a little bit larger than the maximum error  0.0000642481.  After all, it is an error bound.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) John H. Mathews 2004