- #1

- 2

- 0

## Homework Statement

Find all values of a such that

**w**=a

**i**+[itex]\frac{a}{8}[/itex]

**j**is a unit vector.

## Homework Equations

unit vector has length of 1. and for a vector

**v**unit vectors would be

**v**/mag

**v**

## The Attempt at a Solution

1=mag

**w**=\sqrt (a

^{2}+(a/8)

^{2})

1=a

^{2}+(a

^{2}/64)

64=2a

^{2}

32=a

^{2}

a=[itex]\sqrt{32}[/itex]

i know that the solution is: +/- [itex]\frac{8}{\sqrt{65}}[/itex] but am at a loss as to how it was obtained. any help is appreciated.