



When we
write an equation like ...












people
should know what we mean. 





If they
don't, we can draw then a picture ... 











You would
think that would be enough ways to show this. 


Well,
think again. 


It seems
like math people are never satisfied with this stuff. 


Here's
another way to write it ... 





[2, 5)






This is
called interval notation. 


What you
do is list the numbers 


at the
ends of the area that is shaded in the picture. 





If the
endpoint is included, 


you use a
square bracket on that side. 





If the
endpoint is not included, 


you use a
curved bracket on that side. 





If the
shaded area goes to plus or minus infinity, 


that side
always gets a curved bracket. 





So: 








copyright 2005 Bruce Kirkpatrick 
