Example 3. Compare
the "discrete least squares approximation" and "continuous least
squares approximation," on the interval
.
3 (b). Use the
function
.
Solution 3 (b).
![[Graphics:../Images/LegendrePolyMod_gr_110.gif]](../Images/LegendrePolyMod_gr_110.gif)
![[Graphics:../Images/LegendrePolyMod_gr_112.gif]](../Images/LegendrePolyMod_gr_112.gif)
![]()
![[Graphics:../Images/LegendrePolyMod_gr_114.gif]](../Images/LegendrePolyMod_gr_114.gif)
![[Graphics:../Images/LegendrePolyMod_gr_115.gif]](../Images/LegendrePolyMod_gr_115.gif)
![[Graphics:../Images/LegendrePolyMod_gr_116.gif]](../Images/LegendrePolyMod_gr_116.gif)
![[Graphics:../Images/LegendrePolyMod_gr_117.gif]](../Images/LegendrePolyMod_gr_117.gif)
![[Graphics:../Images/LegendrePolyMod_gr_118.gif]](../Images/LegendrePolyMod_gr_118.gif)
![[Graphics:../Images/LegendrePolyMod_gr_119.gif]](../Images/LegendrePolyMod_gr_119.gif)
We are done.
Let us investigate the linear system involved in this example.
![[Graphics:../Images/LegendrePolyMod_gr_121.gif]](../Images/LegendrePolyMod_gr_121.gif)
We are really done.
Aside. We can
calculate the coefficients
by
directly setting up the matrix
vector
. This
is just for fun !
![[Graphics:../Images/LegendrePolyMod_gr_126.gif]](../Images/LegendrePolyMod_gr_126.gif)
This is the same as we obtained previously.
(c) John H. Mathews 2005