Elementary Linear Algebra 7th Edition

Published by Cengage Learning
ISBN 10: 1-13311-087-8
ISBN 13: 978-1-13311-087-3

Chapter 5 - Inner Product Spaces - 5.2 Inner Product Spaces - 5.2 Exercises - Page 246: 71

Answer

(a) The orthogonal projection of $u$ onto $v$ is given by $$\operatorname{proj}_{{v}} {u} = \frac{8}{32}(4,4).$$ (b) The orthogonal projection of $v$ onto $u$ is given by $$\operatorname{proj}_{{u}} {v} = \frac{8}{10}( -1,3).$$

Work Step by Step

Let $u=(-1,3)$, $v=(4,4)$, $\langle{u}, {v}\rangle=u\cdot v$. Then, we have $$\langle{u}, {v}\rangle=8, \quad \langle{u}, {u}\rangle=10, \quad \langle{v}, {v}\rangle=32.$$ (a) The orthogonal projection of $u$ onto $v$ is given by $$\operatorname{proj}_{{v}} {u} =\frac{\langle{u}, {v}\rangle}{\langle{v}, {v}\rangle} {v}=\frac{8}{32}(4,4).$$ (b) The orthogonal projection of $v$ onto $u$ is given by $$\operatorname{proj}_{{u}} {v} =\frac{\langle{u}, {v}\rangle}{\langle{u}, {u}\rangle} {u}=\frac{8}{10}( -1,3).$$ (c)
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.