Online Math Dictionary: U

Easy to understand math definitions for K-Algebra mathematics
Just scroll down or click on the word you want and I'll scroll down for you!
 

undefined undefined slope union of sets

 

Undefined
If the denominator of a fraction is 0, then the fraction is undefined.

undefined fraction 2/0

red line

Undefined Slope
Vertical lines have slopes that are called undefined.  This is because, when you try to find the slope given any two points on the line, you always get a zero in the denominator (for the run):

slope = rise / run = rise / 0

For more info on slopes and vertical lines, check out my lessons on lines.

line with an undefined slope
red line
Union of Sets
The union of two sets is a set of ALL the elements of the two sets.  (You don't write the reruns down twice.)
Example:    A = { 1, 2, 3, a, b, c }     B = { 3, 4, 5, b, c, f, g }
The union is A U B = { 1, 2, 3, 4, 5, a, b, c, f, g }