Precalculus (6th Edition) Blitzer

Published by Pearson
ISBN 10: 0-13446-914-3
ISBN 13: 978-0-13446-914-0

Chapter 6 - Section 6.7 - The Dot Product - Exercise Set - Page 792: 1

Answer

$\mathbf{v}\cdot \mathbf{w}=6$ and $\mathbf{v}\cdot \mathbf{v}=10$

Work Step by Step

The dot product, $\mathbf{v}\cdot \mathbf{w}$ as, $\begin{align} & \mathbf{v}\cdot \mathbf{w=}\left( 3\mathbf{i+j} \right)\cdot \left( \mathbf{i+}3\mathbf{j} \right) \\ & =3\mathbf{i}\cdot \mathbf{i+}3\mathbf{i}\cdot 3\mathbf{j+j}\cdot \mathbf{i+j}\cdot 3\mathbf{j} \\ & =3\left( 1 \right)+9\left( \mathbf{i}\cdot \mathbf{j} \right)+\left( \mathbf{j}\cdot \mathbf{i} \right)+3\left( \mathbf{j}\cdot \mathbf{j} \right) \\ & =3+9\left( 0 \right)+\left( 0 \right)+3\left( 1 \right) \end{align}$ Solve ahead to get the result as, $\begin{align} & \mathbf{v}\cdot \mathbf{w}=3+9\left( 0 \right)+\left( 0 \right)+3\left( 1 \right) \\ & =3+0+0+3 \\ & =6 \end{align}$ The dot product, $\mathbf{v}\cdot \mathbf{v}$ as, $\begin{align} & \mathbf{v}\cdot \mathbf{v=}\left( 3\mathbf{i+j} \right)\cdot \left( 3\mathbf{i+j} \right) \\ & =3\mathbf{i}\cdot 3\mathbf{i+}3\mathbf{i}\cdot \mathbf{j+j}\cdot 3\mathbf{i+j}\cdot \mathbf{j} \\ & =9\left( \mathbf{i}\cdot \mathbf{i} \right)+3\left( \mathbf{i}\cdot \mathbf{j} \right)+3\left( \mathbf{j}\cdot \mathbf{i} \right)+\left( \mathbf{j}\cdot \mathbf{j} \right) \\ & =9\left( 1 \right)+3\left( 0 \right)+3\left( 0 \right)+1 \end{align}$ Solve ahead to get the result as, $\begin{align} & \mathbf{v}\cdot \mathbf{v}=9\left( 1 \right)+3\left( 0 \right)+3\left( 0 \right)+1 \\ & =9+0+0+1 \\ & =10 \end{align}$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.