function x=itfunplot(g,x0,k,a,b)
t=a:(b-a)/999:b;
for i=1:1000
    y1(i)=g(t(i));
end
y2=t;

x=x0;
M=[x0 x0];
for passo=1:k
    M = [M; [x g(x);g(x) g(x)] ];
    x=g(x);
end
plot(t,y1,t,y2,M(:,1),M(:,2));
