% Graphs to demonstrate the definition of limit.
x=0:.005:2; 
y=(x+2).*(x+1).*(x-2).*x.^3+2-1;
xl=x(1:198);
xr=x(204:401);
xrp=x(201:401);
yl=y(1:198);
yr=y(204:401);
yrp=y(201:401);
x0=1;
y0=-5;
subplot(2,2,1)
p1=plot(x,y,'y');
axis([0 2 -15 5])
set(p1,'linewidth',3)
grid
set(gca,'XTick',[0 .5 1 1.5 2])
subplot(2,2,2)
p2=plot(xl,yl,'r',xr,yr,'r');
axis([0 2 -15 5])
set(p2,'linewidth',3)
grid
set(gca,'XTick',[0 .5 1 1.5 2])
subplot(2,2,3)
p3=plot(xl,yl,'c',x0,y0-4,'c.',xr,yr,'c');
axis([0 2 -15 5])
set(p3,'linew',3,'markersize',15)
grid
set(gca,'XTick',[0 .5 1 1.5 2])
subplot(2,2,4)
p4=plot(xl,yl,'g',xrp,-yrp-12,'g');
axis([0 2 -15 5])
set(p4,'linew',3)
grid
set(gca,'XTick',[0 .5 1 1.5 2])