# Unit Vector Problem

#### Tallon

Hello, I am having trouble with the following problem:

If the vector u = (1/2, a, 0, -1/2) is a unit Vector, find possible values of a.

I have the answer key which says 1/2^1/2 and -1/2^1/2 are the possible values of a. It also says that the norm of u is 1. The part I am having trouble with is finding out the norm of u. Once I know the norm I can find a. What am I missing here? Thanks.

Last edited:

#### skipjack

Forum Staff
A unit vector is defined as a vector whose norm is 1.