(b) For the following systems, find the equilibrium point(s), if they exist: (i) \( P_{n+1}=\sqrt{\frac{2 P_{n}+\frac{1}{P_{n}}}{3}} \), where \( P_{n} \neq 0 \) (ii) \( P_{n+1}=\sqrt{\sqrt{\sqrt{256 P_{n}}}} \).
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To find the equilibrium points, we need to set \( P_{n+1} = P_{n} = P^* \) and solve for \( P^* \). (i) Given \( P_{n+1} = \sqrt{\frac{2 P_n + \frac{1}{P_n}}{3}} \), we set \( P^* = \sqrt{\frac{2 P^* + \frac{1}{P^*}}{3}} \). Squaring both sides gives us: \[ (P^*)^2 = \frac{2 P^* + \frac{1}{P^*}}{3} \] Multiplying both sides by 3: \[ 3 (P^*)^2 = 2 P^* + \frac{1}{P^*} \] Rearranging gives: \[ 3 (P^*)^3 - 2 (P^*)^2 - 1 = 0 \] To find the roots, we can use numerical methods or graphing techniques for cubic equations, but one evident root is \( P^* = 1 \). Testing \( P^* = 1 \) in the equation shows it satisfies it, so \( P^* = 1 \) is an equilibrium point. There might be other roots, but they would require further analysis. (ii) For the second system, \( P_{n+1} = \sqrt{\sqrt{\sqrt{256 P_n}}} \), we again set \( P^* = \sqrt{\sqrt{\sqrt{256 P^*}}} \). Squaring both sides multiple times gives us: 1st squaring: \[ (P^*)^2 = \sqrt{256 P^*} \] 2nd squaring: \[ (P^*)^4 = 256 P^* \] Rearranging leads us to: \[ (P^*)^4 - 256 P^* = 0 \] Factoring: \[ P^* ((P^*)^3 - 256) = 0 \] This gives the solutions \( P^* = 0 \) or \( (P^*)^3 = 256 \), which means \( P^* = 4 \). Thus, the equilibrium points are \( P^* = 0 \) and \( P^* = 4 \).