**Problem : **
What is the difference between a vector and a ray?

A vector has finite length, whereas a ray extends in one direction without
limit.

**Problem : **
A vector has origin at (1,2) and endpoint at (-3,-4). What is the horizontal,
or *x*-component of this vector?

-4

**Problem : **
How many vectors are needed to form the coordinate plane?

An infinite number. Vectors have finite length--therefore it requires an
infinite number of vectors to form the coordinate plane, which extends in all
directions without limit.

**Problem : **
A vector has origin at (-3,5) and endpoint at (0,8). What is the magnitude of
this vector?

= 3