Precalculus (6th Edition) Blitzer

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

Chapter 6 - Section 6.6 - Vectors - Exercise Set - Page 782: 70

Answer

The length of the shadow is $\left| \left| \text{1}\text{.4} \right| \right|\text{=1}\text{.4 inches}$.

Work Step by Step

The magnitude and direction of the vector are given. Analyze the vector and resolve it into its horizontal and vertical components. The vector component along the x-axis or the horizontal direction is i and the vector component along the y-axis or the vertical direction is j. Therefore, the equation becomes $\begin{align} & \mathbf{v}=\left| \left| \mathbf{v} \right| \right|\text{cos}\theta \mathbf{i}+\left| \left| \mathbf{v} \right| \right|\text{sin}\theta \mathbf{j} \\ & =\text{1}\text{.8cos}40{}^\circ \mathbf{i}+\text{1}\text{.8sin}40{}^\circ \mathbf{j} \\ & =\text{1}\text{.4}\mathbf{i}+1.2\mathbf{j} \end{align}$ The shadow forms on the x-axis; therefore, only the horizontal component is taken and the vertical component is ignored.
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