(30, 40)T  =  10(3, 4)T, so the length is 10*5   =   50

Or, if you want to do it the hard way:

|(30,40)|2  =  900 + 1600  =  2500. The length  =  2500  =  50.

# Unit Vectors

Recall that a unit vector is a vector of length one. Creating a unit vector in the same direction as a given vector is called normalizing the vector. Here is the formula for normalizing a vector (copied from a previous chapter):

 vu  =  v / |v|

The formula works both for vectors and the column matrices that represent them. The length | v | can be calculated by using the column matrix dot product.

Potential Confusion: The word "normal" has several meanings. Normalizing a vector means making a unit vector in the same direction as the original. A vector that is perpendicular to a particular surface is sometimes called a "normal vector" but is not necessarily a unit vector. Be careful never to say "normal vector" when you mean "unit vector."

### QUESTION 4:

(Calculator Problem: ) Normalize the vector represented by ( 1.2, -4.2, 3.5 )T.