% relation_ex.m
% kris stewart, cs 205, spring '98
% examples using relational operators on vectors
%
clear
close all
clc
%-------------------------------------------------------------------

echo on
x1 = -3:.1:3;		% set up a range of values

y1 = sin(x1)./x1;	% given these values of x, compute  sin(x)/x
			% What does l'Hospital's Rule say about 
			% sin(x)/x as x -> 0?
%
% you probably got a message about divide by zero.
%

x2 = x1+(x1==0)*eps;	% replace x with eps if it's component was zero

y2 = sin(x2)./x2;		% try to compute sin(x)/x

%
% no divide by zero message this time, right?
%
% to validate this, let's plot the function sin(x)/x and see what it's
% graph reveals about its behavior near x=0
figure
x = linspace(-3,3,50);
y =  sin(x)./x;
plot(x,y), grid, title('Looks nicely behaved to me'),...
xlabel('x'),ylabel('sin(x)/x')