
(e) When u
E
¼20, the ‘‘roots’’ function in ‘‘ Chap7_Ex2_1.m’’ yields three solutions to Equation
7.25, namely, 0.1814, 1.3278, and 2.4908.
(f) Using the ‘‘trim’’ function with initial state guesses of 0, 2, and 5 produces the identical
equilibrium states (see Cases B.1, B.2, and B.3 in Table 7.2).
(g) The stability of each equilibrium point can be ascertained by looking at a graph of the
growth rate function shown in Figure 7.10. Note that the fish density increases wherever g(x)
is positive as indicated by right-pointing arrows and conversely decreases in regions where g(x)is
negative, shown with left-pointing arrows. Fish densities initially located ...