Math Problem Statement

Consider the statements regarding the discrete-time dynamical system m_{t+1} = f(m_t) based on the graph provided. Evaluate the following statements: 1. The solution starting at m_0 = 0.5 is increasing. 2. The solution starting at m_0 = 1.25 is increasing. 3. m^* = 0 is a stable equilibrium. 4. The non-zero equilibrium is unstable. Determine which statements are True (1) or False (2).

Solution

From the image provided, we need to evaluate the statements regarding the discrete-time dynamical system mt+1=f(mt)m_{t+1} = f(m_t), based on the graph given. The graph shows a blue curve representing f(m)f(m) and a red line mt+1=mtm_{t+1} = m_t (the identity line). Let’s analyze the statements:

Analysis

  1. Statement (i): The solution starting at m0=0.5m_0 = 0.5 is increasing.

    • From the graph, f(0.5)>0.5f(0.5) > 0.5, indicating that mt+1>mtm_{t+1} > m_t. Therefore, the solution starting at m0=0.5m_0 = 0.5 increases.
    • This statement is True (1).
  2. Statement (ii): The solution starting at m0=1.25m_0 = 1.25 is increasing.

    • From the graph, f(1.25)<1.25f(1.25) < 1.25, indicating that mt+1<mtm_{t+1} < m_t. Therefore, the solution starting at m0=1.25m_0 = 1.25 decreases.
    • This statement is False (2).
  3. Statement (iii): m=0m^* = 0 is a stable equilibrium.

    • At m=0m^* = 0, the graph intersects the line mt+1=mtm_{t+1} = m_t. However, the slope of f(m)f(m) near m=0m^* = 0 appears to be less steep than 1, indicating stability.
    • This statement is True (1).
  4. Statement (iv): The non-zero equilibrium is unstable.

    • There is another equilibrium where the blue curve intersects the red line (non-zero equilibrium). Observing the graph, the slope of f(m)f(m) near this equilibrium is greater than 1, indicating instability.
    • This statement is True (1).

Final Answer

The correct sequence is 1, 2, 1, 1.

Would you like me to explain any step in more detail or analyze additional scenarios?

Related Questions:

  1. How can you determine stability for equilibrium points in a discrete dynamical system?
  2. What role does the slope of f(m)f(m) play in determining stability?
  3. How would the analysis change if f(m)f(m) had a different shape?
  4. What are the implications of unstable equilibria in real-world systems?
  5. How does the graph illustrate the long-term behavior of solutions for varying m0m_0?

Tip:

Always evaluate the slope of f(m)f(m) at equilibrium points to determine whether they are stable (f(m)<1|f'(m^*)| < 1) or unstable (f(m)>1|f'(m^*)| > 1).

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Math Problem Analysis

Mathematical Concepts

Discrete-time dynamical systems
Equilibria
Stability analysis
Graphical analysis

Formulas

m_{t+1} = f(m_t)
Stability condition: |f'(m^*)| < 1

Theorems

Stability theorem for fixed points in discrete dynamical systems

Suitable Grade Level

Undergraduate mathematics or advanced high school calculus