Texas Instruments TI-84 PLUS SILV Guidebook - Page 118

6. Press p and change the variables below. Xmin=L10 Xmax=10 7. Press s to graph the sequence. 8. Press r, and then press ~ to draw the web. The displayed cursor coordinates n, X (u(nN1)), and Y (u(n)) change accordingly. When you press ~, a new n value is displayed, and the trace cursor is on the sequence. When you press ~ again, the n value remains the same, and the cursor moves to the y=x reference line. This pattern repeats as you trace the web. Graphing Phase Plots Graphing with uv, vw, and uw The phase-plot axes settings uv, vw, and uw show relationships between two sequences. To select a phase-plot axes setting, press y ., press ~ until the cursor is on uv, vw, or uw, and then press Í. Axes Setting uv vw uw x-axis u(n) v(n) u(n) y-axis v(n) w(n) w(n) Example: Predator-Prey Model Use the predator-prey model to determine the regional populations of a predator and its prey that would maintain population equilibrium for the two species. This example uses the model to determine the equilibrium populations of foxes and rabbits, with initial populations of 200 rabbits (u(nMin)) and 50 foxes (v(nMin)). These are the variables (given values are in parentheses): R = number of rabbits M = rabbit population growth rate without foxes K = rabbit population death rate with foxes W = number of foxes G = fox population growth rate with rabbits (.05) (.001) (.0002) Chapter 6: Sequence Graphing 111