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

Solution 2 (e).

Investigate the error over the interval  [Graphics:../Images/NewtonPolyMod_gr_319.gif]  for the Newton interpolation polynomial  [Graphics:../Images/NewtonPolyMod_gr_320.gif],  of degree n = 5.

[Graphics:../Images/NewtonPolyMod_gr_321.gif]

[Graphics:../Images/NewtonPolyMod_gr_322.gif]

[Graphics:../Images/NewtonPolyMod_gr_323.gif]
[Graphics:../Images/NewtonPolyMod_gr_324.gif]

[Graphics:../Images/NewtonPolyMod_gr_325.gif]
[Graphics:../Images/NewtonPolyMod_gr_326.gif]
[Graphics:../Images/NewtonPolyMod_gr_327.gif]

[Graphics:../Images/NewtonPolyMod_gr_328.gif]

Use formula (v).    [Graphics:../Images/NewtonPolyMod_gr_329.gif][Graphics:../Images/NewtonPolyMod_gr_330.gif]   is valid for  [Graphics:../Images/NewtonPolyMod_gr_331.gif],  and find the error bound for this example.

[Graphics:../Images/NewtonPolyMod_gr_332.gif]

[Graphics:../Images/NewtonPolyMod_gr_333.gif]

[Graphics:../Images/NewtonPolyMod_gr_334.gif]
[Graphics:../Images/NewtonPolyMod_gr_335.gif]
[Graphics:../Images/NewtonPolyMod_gr_336.gif]
[Graphics:../Images/NewtonPolyMod_gr_337.gif]

[Graphics:../Images/NewtonPolyMod_gr_338.gif]

Thus,  [Graphics:../Images/NewtonPolyMod_gr_339.gif]   is valid for  [Graphics:../Images/NewtonPolyMod_gr_340.gif],  which is a little bit larger than the maximum error  [Graphics:../Images/NewtonPolyMod_gr_341.gif].  After all, it is an error bound.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) John H. Mathews 2004