created 08/26/97; revised 08/12/00, 07/22/03, 07/22/09, 01/11/15

This chapter discusses how to multiply a
vector by a real number (called **scaling**),
and how this is used to construct **unit vectors**.
Unit vectors are used to
show direction in 3D space,
and are essential for 3D graphics.

- Scaling
- Unit vectors
- Normalizing a vector
- Variables in vector equations

Change the elements of this column matrix: (3, 4)^{T}
so that the vector it represents
is twice as long and remains pointing in the same direction.
(Officially you don't know how to do this. Take a guess.)