Calculus, 10th Edition (Anton)

Published by Wiley
ISBN 10: 0-47064-772-8
ISBN 13: 978-0-47064-772-1

Chapter 11 - Three-Dimensional Space; Vectors - 11.2 Vectors - Exercises Set 11.2 - Page 782: 16

Answer

Yes, for two parallel vectors in the same direction $\lambda \vec{v}=\vec{u} , \lambda>1$

Work Step by Step

Yes, it's possible. Let $\vec{v}$ and $\vec{u}$ two parallel vectors, and then \[ \begin{aligned} \lambda \vec{v}=\vec{u} \Rightarrow \quad\|\vec{v}+\vec{u}\| &=\|\lambda \vec{v}+\vec{v}\ |=\|(1+\lambda) \vec{v}\| \\ &=\|\vec{v}\| |1+\lambda| \end{aligned} \] For $\lambda>1$, we have two parallel vectors in the same direction and \[ \begin{aligned} \|\vec{v}+\vec{u}\| &=\|\vec{v}\|(1+\lambda)=\|\vec{v}\| +\lambda\|\vec{v}\|\\ &=\|\vec{v}\| +\|\lambda \vec{v}\|=\|\vec{v}\|+\|\vec{u}\| \end{aligned} \]
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.