Plot phase plane for system of differential equations I'm in need of some help with matlab code.  I'm working on a problem which gives the following system:
$$x'=x^2 - x - y$$
$$y'=x-y$$
We are asked to solve the system numerically starting with $(x(0), y(0))=(-0.3,-0.3)$ for $t \in [0,10]$. Additionally, we are asked to plot the solution in a phase plane and also as a function of time.
My initial reaction is to try and use the ode45 function, then plot the $x$ and $y$ components as functions of time.  The thing that I'm really having trouble with is plotting the phase plane...
Any help/links/advice is greatly appreciated!

The phase portrait of a system of two first-order ODEs can be obtained in a similar manner as described in this post, e.g. using Matlab's quiver function. Otherwise, one can plot several trajectories $(x (t), y (t))$ obtained by numerical integration (here with ode45) and having different initial conditions.
