Positive Periodic Solutions of Nicholson-Type Delay Systems with Nonlinear Density-Dependent Mortality Terms

Figure 1

Numerical solution 𝑁(𝑡)=(𝑁₁(𝑡),𝑁₂(𝑡))^𝑇 of systems (3.1) for initial value 𝜑(𝑡)≡(1,2)^𝑇.

(a)

(b)