Example 12.  Plot the solutions to the D. E.  [Graphics:Images/HarvestingModelMod_gr_223.gif]  in Example 9
that have the following initial conditions  [Graphics:Images/HarvestingModelMod_gr_224.gif].

Solution 12.

We could try the above technique where we solve  [Graphics:../Images/HarvestingModelMod_gr_225.gif]  for  [Graphics:../Images/HarvestingModelMod_gr_226.gif].
But it will involve complex numbers.  Hang in there !

[Graphics:../Images/HarvestingModelMod_gr_227.gif]

[Graphics:../Images/HarvestingModelMod_gr_228.gif]

Notice that there are multiple solutions for some of these values.
Special care and attention must be given to locate the ones to use, they are:
[Graphics:../Images/HarvestingModelMod_gr_229.gif]
Now replace these constants.

[Graphics:../Images/HarvestingModelMod_gr_230.gif]

[Graphics:../Images/HarvestingModelMod_gr_231.gif]

Make them look nicer.  

[Graphics:../Images/HarvestingModelMod_gr_232.gif]

[Graphics:../Images/HarvestingModelMod_gr_233.gif]

It might be better to just solve the D.E. with the required initial conditions.

[Graphics:../Images/HarvestingModelMod_gr_234.gif]

[Graphics:../Images/HarvestingModelMod_gr_235.gif]

Then form the construction with the following two steps.

[Graphics:../Images/HarvestingModelMod_gr_236.gif]

[Graphics:../Images/HarvestingModelMod_gr_237.gif]

[Graphics:../Images/HarvestingModelMod_gr_238.gif]

[Graphics:../Images/HarvestingModelMod_gr_239.gif]

They is algebraically the same as the list that was obtained using those pesky complex numbers.

Graph these solutions.

[Graphics:../Images/HarvestingModelMod_gr_240.gif]


[Graphics:../Images/HarvestingModelMod_gr_241.gif]

[Graphics:../Images/HarvestingModelMod_gr_242.gif]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(c) John H. Mathews 2004