plotting - How do I plot x[t] vs. x'[t] (where x[t] and x'[t] are solutions to NDSolve)?

I have a differential equation which I solved using NDSolve. I can easily plot x[t] vs. t, x'[t] vs. t, but....

how do I plot x[t] vs. x'[t]?

I tried using the Evaluate function to simplify things, but I still have no luck. Here's what I mean:

x1 = Evaluate[x'[t] /. sol];

x2 = Evaluate[x[t] /. sol];

Plot[x2, {x1, 0, 50}, PlotRange -> Automatic, AxesLabel -> {x[t], x'[t]}]

How can I plot these? This approach also did not work:

Plot[x[t]/.sol, {x'[t]/.sol, 0, 50}, PlotRange -> Automatic, 
AxesLabel -> {x[t], x'[t]}]

Help!

Comments

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