Hello, I'm considering the system:(adsbygoogle = window.adsbygoogle || []).push({});

dx/dt=y-x

dy/dt=x-y

I've found the fixed points and shown that this is a first integral of the system:

f(x,y)=x+y

How can I (using this information only) sketch a phase portrait? I know the graph of fixed points looks like the x=y graph, but im not sure how this relates to a phase portrait.

Any help? Thanks.

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# Phase Portrait Question

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