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Ch. 4 - Laws of Sines and Cosines; Vectors
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Non è quello che usi tu?Cambia libro di testo
Capitolo 4, Problema 4.40

In Exercises 39–46, find the unit vector that has the same direction as the vector v.
v = -5j

Guida verificata passo dopo passo
1
Identify the given vector \( \mathbf{v} = -5\mathbf{j} \). This means the vector points in the negative y-direction with a magnitude of 5.
Recall that the unit vector \( \mathbf{u} \) in the direction of \( \mathbf{v} \) is found by dividing \( \mathbf{v} \) by its magnitude \( \|\mathbf{v}\| \). The formula is: \[ \mathbf{u} = \frac{\mathbf{v}}{\|\mathbf{v}\|} \]
Calculate the magnitude of \( \mathbf{v} \). Since \( \mathbf{v} = 0\mathbf{i} - 5\mathbf{j} \), the magnitude is: \[ \|\mathbf{v}\| = \sqrt{0^2 + (-5)^2} = \sqrt{25} \]
Divide each component of \( \mathbf{v} \) by the magnitude \( \|\mathbf{v}\| \) to get the unit vector components: \[ \mathbf{u} = \left( \frac{0}{\|\mathbf{v}\|}, \frac{-5}{\|\mathbf{v}\|} \right) \]
Write the unit vector \( \mathbf{u} \) in terms of the unit vectors \( \mathbf{i} \) and \( \mathbf{j} \) using the components found in the previous step.

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