Example 10. Use
Mathematica to find the analytic solution and graph for the
I.V.P.
.
Solution 10.
Dig out the formula for the solution out of the data structure
of solset and put it in f[t].
Plot the analytic solution at the same sample points that were used
for the numerical approximations.
![[Graphics:../Images/MilneSimpsonMod_gr_156.gif]](../Images/MilneSimpsonMod_gr_156.gif)
Just for fun, plot the Milne-Simpson solution and the analytic solution. Notice that there is a difference.
![[Graphics:../Images/MilneSimpsonMod_gr_160.gif]](../Images/MilneSimpsonMod_gr_160.gif)
![[Graphics:../Images/MilneSimpsonMod_gr_163.gif]](../Images/MilneSimpsonMod_gr_163.gif)
Something strange is happening, it appears that the solution
to
has
a vertical asymptote, yet Milne-Simpson's method is able to move past
this asymptote! How can this happen? If the
step size is chosen smaller, then these methods will not tend to
overshoot the asymptote. The location of the asymptote can be found
using Mathematica's procedure FindRoot.
Numerical methods with a higher order of precision will not tend to overshoot the asymptote.
(c) John H. Mathews 2004