Example 8. Compare
the "discrete interpolation polynomial" and "Legendre series
approximation," on the interval
.
8 (b). Use the
function
.
Solution 8 (b).
![[Graphics:../Images/LegendrePolyMod_gr_337.gif]](../Images/LegendrePolyMod_gr_337.gif)
![[Graphics:../Images/LegendrePolyMod_gr_338.gif]](../Images/LegendrePolyMod_gr_338.gif)
Details for this computation.
First, construct the coefficients.
![[Graphics:../Images/LegendrePolyMod_gr_340.gif]](../Images/LegendrePolyMod_gr_340.gif)
Construct the terms.
![[Graphics:../Images/LegendrePolyMod_gr_342.gif]](../Images/LegendrePolyMod_gr_342.gif)
![[Graphics:../Images/LegendrePolyMod_gr_343.gif]](../Images/LegendrePolyMod_gr_343.gif)
Then add up the terms.
![[Graphics:../Images/LegendrePolyMod_gr_345.gif]](../Images/LegendrePolyMod_gr_345.gif)
(c) John H. Mathews 2005