Math Problem Statement

Find the vector v with the given length and the same direction as u, where ||v|| = 3 and u = (0, -1, -1, 4).

Solution

Let's solve this step by step based on the problem shown in the image:

Problem

We are tasked to find a vector v\mathbf{v} with a given magnitude v=3\| \mathbf{v} \| = 3 and in the same direction as u=(0,1,1,4)\mathbf{u} = (0, -1, -1, 4).


Step 1: Normalize the vector u\mathbf{u}

To create a vector in the same direction as u\mathbf{u}, we first compute the unit vector uunit\mathbf{u}_{\text{unit}} by dividing u\mathbf{u} by its magnitude.

  1. Magnitude of u\mathbf{u}:

    u=(0)2+(1)2+(1)2+(4)2=0+1+1+16=18=32\| \mathbf{u} \| = \sqrt{(0)^2 + (-1)^2 + (-1)^2 + (4)^2} = \sqrt{0 + 1 + 1 + 16} = \sqrt{18} = 3\sqrt{2}

  2. Unit vector uunit\mathbf{u}_{\text{unit}}:

    Divide each component of u\mathbf{u} by u\| \mathbf{u} \|:

    = \left( 0, \frac{-1}{3\sqrt{2}}, \frac{-1}{3\sqrt{2}}, \frac{4}{3\sqrt{2}} \right).$$

Step 2: Scale the unit vector to magnitude 3

To make the vector v\mathbf{v} have a magnitude of 3, multiply the unit vector uunit\mathbf{u}_{\text{unit}} by 3:

= \left( 3 \cdot 0, 3 \cdot \frac{-1}{3\sqrt{2}}, 3 \cdot \frac{-1}{3\sqrt{2}}, 3 \cdot \frac{4}{3\sqrt{2}} \right).$$ Simplify: $$\mathbf{v} = \left( 0, \frac{-1}{\sqrt{2}}, \frac{-1}{\sqrt{2}}, \frac{4}{\sqrt{2}} \right).$$ Further simplify by rationalizing the denominator: $$\mathbf{v} = \left( 0, -\frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2}, 2\sqrt{2} \right).$$ --- ### Final Answer: $$\mathbf{v} = \left( 0, -\frac{\sqrt{2}}{2}, -\frac{\sqrt{2}}{2}, 2\sqrt{2} \right).$$ Let me know if you would like further clarification! --- ### Follow-Up Questions: 1. How do you compute the magnitude of a 4-dimensional vector? 2. Why is it important to normalize a vector when scaling to a specific magnitude? 3. What happens if $$\mathbf{u}$$ has a magnitude of 0? 4. Can the unit vector have a magnitude other than 1? 5. How do rationalization steps simplify results in vector calculations? ### Tip: Always double-check the denominator when rationalizing square roots to ensure correctness.

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Math Problem Analysis

Mathematical Concepts

Vector Normalization
Scaling Vectors
Vector Magnitude

Formulas

||u|| = sqrt(u1^2 + u2^2 + ... + un^2)
u_unit = u / ||u||
v = k * u_unit, where ||v|| = k

Theorems

Pythagorean Theorem (for magnitude)

Suitable Grade Level

Undergraduate Math