Exercise B. Consider the spruce budworm model.

A bifurcation occurs approximately at the point (k, r) = (9.57, 0.4). Sketch the graph of the curve X /1+X^2 and line r (1 X /k )for this situation (similarly to what we have done in class). Make sure to label your axes. Then use the over-under method to draw the associated phase portrait, indicating the stability of the equilibrium point(s).