Example 7. Start
with
over
the interval
. Use
the Gram-Schmidt orthogonalization to construct a few of the
orthogonal polynomials
over
the interval
. Construct
the corresponding Legendre
polynomials
.
Solution 7.
We can let Mathematica do it all using recursion as follows. First define the inner product and the recursive formulas.
![[Graphics:../Images/LegendrePolyMod_gr_281.gif]](../Images/LegendrePolyMod_gr_281.gif)
The polynomials are generated using the above recursive formulas.
![[Graphics:../Images/LegendrePolyMod_gr_283.gif]](../Images/LegendrePolyMod_gr_283.gif)
Details
Set up the inner product function.
![[Graphics:../Images/LegendrePolyMod_gr_284.gif]](../Images/LegendrePolyMod_gr_284.gif)
Construct the first few orthogonal polynomials.
![[Graphics:../Images/LegendrePolyMod_gr_286.gif]](../Images/LegendrePolyMod_gr_286.gif)
![[Graphics:../Images/LegendrePolyMod_gr_288.gif]](../Images/LegendrePolyMod_gr_288.gif)
![[Graphics:../Images/LegendrePolyMod_gr_289.gif]](../Images/LegendrePolyMod_gr_289.gif)
![[Graphics:../Images/LegendrePolyMod_gr_290.gif]](../Images/LegendrePolyMod_gr_290.gif)
![[Graphics:../Images/LegendrePolyMod_gr_291.gif]](../Images/LegendrePolyMod_gr_291.gif)
![[Graphics:../Images/LegendrePolyMod_gr_292.gif]](../Images/LegendrePolyMod_gr_292.gif)
![[Graphics:../Images/LegendrePolyMod_gr_293.gif]](../Images/LegendrePolyMod_gr_293.gif)
![[Graphics:../Images/LegendrePolyMod_gr_294.gif]](../Images/LegendrePolyMod_gr_294.gif)
![[Graphics:../Images/LegendrePolyMod_gr_295.gif]](../Images/LegendrePolyMod_gr_295.gif)
These orthogonal polynomials are related to the Legendre
polynomials, all we need to do is normalize them so
that
.
![[Graphics:../Images/LegendrePolyMod_gr_298.gif]](../Images/LegendrePolyMod_gr_298.gif)
![[Graphics:../Images/LegendrePolyMod_gr_299.gif]](../Images/LegendrePolyMod_gr_299.gif)
![[Graphics:../Images/LegendrePolyMod_gr_300.gif]](../Images/LegendrePolyMod_gr_300.gif)
![[Graphics:../Images/LegendrePolyMod_gr_301.gif]](../Images/LegendrePolyMod_gr_301.gif)
![[Graphics:../Images/LegendrePolyMod_gr_302.gif]](../Images/LegendrePolyMod_gr_302.gif)
![[Graphics:../Images/LegendrePolyMod_gr_304.gif]](../Images/LegendrePolyMod_gr_304.gif)
(c) John H. Mathews 2005