- #1

JoeTrumpet

- 43

- 0

## Homework Statement

Given vectors v and w, show that |v*w| =< |v|*|w|

## Homework Equations

I know that |v| = sqrt((x1)^2+(x2)^2+...+(xn)^2)

and that |w| = sqrt((y1)^2+(y2)^2+...+(yn)^2)

also |v*w| = x1y1 + x2y2 + ... + xnyn

We were also told

Hint: use |v+c*w|^2

and (v+c*w)(v+c*w)

## The Attempt at a Solution

I am not at all sure what to do. I distributed the second expression in the hint to get

w^2 + 2vwc + c^2*v^2, but that doesn't tell me much.

Thanks!