programmatara 10 seirwn :p

function s = logstep(r,x,n)

a=1:n;
b=1:n;

a(1)=0;
b(1)=x;


for i=2:n
    b(i) = r * b(i-1) * (1 - b(i-1));
    a(i) = i;
end

z=[a,b];

plot(z,'-o');
s=x;