How to use three differential equation in pplane in Matlab?

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Ali 2016-3-19

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回答： Walter Roberson 2022-9-24

Hi. I am trying to analyse 2 pray and 1 predator system using pplane in Matlab. So, I should use 3 equations but pplane8 just enables us to use 2 equations. Can anyone suggest a solution to use 3 equations? Thank you...

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miqin 2022-9-24

编辑：miqin 2022-9-24

Hi, does Star. pplane8 apply to three differential equations ? If possible, how should I set them ? Thanks@Star Strider

Walter Roberson 2022-9-24

pplane8 is https://www.mathworks.com/matlabcentral/fileexchange/61636-pplane

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Answer 1

Gopal Sarkar 2019-7-29

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I have same quries regarding this. Anyone help us ?

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Answer 2

Walter Roberson 2022-9-24

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dfield is for one differential equation, pplane is for two differential equations, for studying phase planes.

The software is not designed for 3 differential equations and would have to be extended for 3 or more equations.

That would include having to revise the graphics system in order to be able to to examine interactions between any two equations, and study the three together. Plotting with two or three independent inputs and three outputs would require graphics in 5 or 6 dimensions, which is a problem.

The authors do not appear to be working on extending the software; it is at least 18 years old now.