%Matlab code for Exercise 1(c,d), page 67 (Devaney's text)

%Change the code below for 1(c,d).  It is set up to see 1(c).
%  To see 1(d), comment out line 9 (percentage sign in front),
%  remove the comment from line 10 (delete the percent sign)
%  and change y2 back to y1 in line 17 (unless you want to see the second
%  iterate).

cvals=0:-0.05:-1.5; %Choose a range for the bifurcation parameter
%cvals=0:0.05:1.5;  %Parameter range for 1(d)

N=length(cvals);  %Number of plots in the animation
x=linspace(-2,2,200);  %Domain of the plot- the interval from -2 to 2
for j=1:N
    y1=cvals(j)*x+x.^3;
    y2=cvals(j)*y1+y1.^3;  %Second composition, if desired
    plot(x,x,x,y2);        %Change the last entry to y1, y2
                           %  These correspond to F, F^2, F^3, F^4
    axis([-2,2,-2,2]);
    fprintf('c value is %f \n',cvals(j))
    pause
end