%This is a for class example of Taylor series approximation
dx=1./100;
x=[-2:dx:2];
%create a vector of ones the same size of x
s1=ones(size(x));
s2=s1-x; 
%the dot in "x.^2" is to square each element of x separately
s3=s2+x.^2/2; 
s4=s3-x.^3/6;
plot(x,s1,'--')
%the hold on means the next plot is overlaid on the old plot--type hold off to unset this
hold on
plot(x,s2,'-.')
plot(x,s3,':')
plot(x,s4)
plot(x,exp(-x),'.');
xlabel('x')
ylabel('y')
title('Taylor Series Approximation of exp(-x)')
text(1,7,'s1 --')
text(1,6.5,'s2 -.')
text(1,6.0,'s3 :')
text(1,5.5,'s4 -')
text(1,5.0,'exp(-x) fat line')
hold off;