set notation question

[khorven]

I just started reading my math textbook and I don't understand this set notation:
http://i247.photobucket.com/albums/gg140/royiz/Untitled-1.jpg

the |x E D} part is what I'm having trouble with. What is that saying?

 

[mmm4444bot]

[attachment=0:3cwtz14e]SetNotation.JPG[/attachment:3cwtz14e]

This is basically read as: "The set of all ordered pairs (x, y) that satisfy y = f(x), such that x is an element of the domain of f."

The symbol | means "such that".

The symbol ? means "is an element of".

In this exercise, the symbol D represents "the domain of function f" (which is yet another set).

Of course, curly braces denote {a set of objects}.

If f(x) = x + 5, then the set above contains the coordinates for the infinite points that make up the line.

 

[khorven]

I see, thanks for the explanation.