dy/dx = x^{2} − y^{2}

dy/dx = x − xy: solution curves y = ce^{−x2/2} +
1

dy/dx = y^{2} − 3y: *y* = 0 is stable (attractor),
*y* = 3 is unstable (repeller)

dy/dx = y^{2}(*2 − y*): *y* = 0 is
semi-stable, *y* = 2 is stable (repeller)

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