 
Summary: Math 308, Matlab assignment 2
due October 14 in class
plot(x,y) plots entries of the vector y versus entries of the vector x. plot(x1,y1,x2,y2)
plots two graphs on the same plot. They are automatically done in different colors. You can also
modify the style of each graph: try plot(x1,y1,'x:',x2,y2,'') and use help plot
for more details. You can also add a new graph to the previous plot by using hold on / hold
off commands. Use legend('first graph','second graph') to label the graphs,
xlabel('x'), ylabel('y'), title('Title') to label the axes and the figure, and
grid on to add a grid if you want.
1. The file RPS.m models the evolution of interacting RockPaperScissors populations. With the
growth parameter a = 1.1 and initial conditions R(0) = 2, P(0) = 0.5, S(0) = 1, answer the
following question: which population is the largest at the time
(a) t = 1
(b) t = 5
(c) t = 10?
You can attach the plots if you like. The easiest way to do this problem is to imitate what is done in
the diary.
2. The predatorprey equations are also called the LotkaVolterra equations. They were originally
introduced in the 1920's by the Italian mathematician Umberto Volterra to explain why, during the
first World War, a larger percentage of catch of Italian fishermen consisted of sharks and other fish
