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Let \(\mathbf{u}=\langle 3,-4\rangle, \mathbf{v}=\langle 1,1\rangle,\) and \(\mathbf{w}=\langle 1,0\rangle\) $$\text { Find }|2 \mathbf{u}+3 \mathbf{v}-4 \mathbf{w}|$$

Short Answer

Expert verified
Answer: The magnitude of the vector is \(\sqrt{50}\).

Step by step solution

01

Calculate the resulting vector

We are given the following vectors: \(\mathbf{u}=\langle 3,-4\rangle\), \(\mathbf{v}=\langle 1,1\rangle,\) and \(\mathbf{w}=\langle 1,0\rangle\). We need to find the vector \(2\mathbf{u} + 3\mathbf{v} - 4\mathbf{w}\). This can be done by adding the corresponding components of the vectors and then multiplying them by the given constants: $$ 2\mathbf{u} + 3\mathbf{v} - 4\mathbf{w} = 2\langle 3,-4\rangle + 3\langle 1,1\rangle - 4\langle 1,0\rangle $$ Now, let's calculate the resulting vector: $$ 2\langle 3,-4\rangle + 3\langle 1,1\rangle - 4\langle 1,0\rangle = \langle 2(3), 2(-4)\rangle + \langle 3(1), 3(1)\rangle - \langle 4(1), 4(0)\rangle $$ $$ = \langle 6,-8 \rangle + \langle 3,3 \rangle - \langle 4,0 \rangle $$ $$ = \langle 6+3-4,-8+3+0 \rangle = \langle 5,-5 \rangle $$ So, the resulting vector is \(\langle 5, -5 \rangle\).
02

Calculate the magnitude of the resulting vector

Now that we have the resulting vector \(\langle 5,-5\rangle\), we can calculate its magnitude. The magnitude of a 2-dimensional vector \(\langle x,y \rangle\) is given by the formula: $$ |\mathbf{v}| = \sqrt{x^2 + y^2} $$ Thus, the magnitude of our vector \(\langle 5,-5\rangle\) is: $$ |\langle 5,-5\rangle| = \sqrt{ (5)^2 + (-5)^2 } $$ $$ = \sqrt{ 25 + 25 } = \sqrt{50} $$ So, the magnitude of the resulting vector is \(\sqrt{50}\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Vector Addition
Vector addition is a fundamental concept in mathematics and physics. It involves combining vectors to form a new vector. In simpler terms, when you add two or more vectors, you combine their magnitudes and directions. This process is performed component-wise, which means you add each corresponding component of the vectors together.

For instance, to add vectors \( \mathbf{u}=\langle 3,-4\rangle \), \( \mathbf{v}=\langle 1,1\rangle \), and \( \mathbf{w}=\langle 1,0\rangle \), each component is added separately:
  • Add the \( x \)-components: \( 3+1+1 \)
  • Add the \( y \)-components: \( -4+1+0 \)
By performing these operations, we can simplify and find the resulting vector. This is particularly useful when graphically demonstrating vector addition as the resultant vector's tail can be placed at the head of the last vector in the sequence.
Vector Subtraction
Subtraction of vectors is slightly different from addition. It involves finding the vector difference, or in simple words, how much one vector changes to become another. Just like addition, vector subtraction is performed component-wise.

If we take the vectors \( \mathbf{u} \) and \( \mathbf{w} \), the subtraction \( \mathbf{u} - \mathbf{w} \) is calculated by:
  • Subtract the \( x \)-components: \( 3-1 \)
  • Subtract the \( y \)-components: \(-4-0 \)
In our problem, you would handle operations like \(-4\mathbf{w}\) by distributing the scalar, \(-4\), to each component of \( \mathbf{w} \). This process helps to adjust the direction and magnitude as required and is crucial when forming resultant vectors that require both addition and subtraction.
Vector Components
Vector components refer to the breakdown of a vector into its parts, specifically its \( x \)- and \( y \)-components in a two-dimensional vector space. Understanding these components is key to performing vector addition and subtraction effectively.

In this case, our vectors \( \mathbf{u} \), \( \mathbf{v} \), and \( \mathbf{w} \) have clear components. For example, \( \mathbf{u} = \langle 3, -4 \rangle \) has an \( x \)-component of 3 and a \( y \)-component of -4. Identifying and using these components individually allow you to manipulate vectors mathematically.
  • The \( x \)-component relates to horizontal movement or influence.
  • The \( y \)-component accounts for vertical direction.
By working with vector components, it's easier to apply vector operations such as scaling by multiplying by a constant or combining through addition and subtraction.

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Most popular questions from this chapter

Suppose \(\mathbf{u}\) and \(\mathbf{v}\) are vectors in the plane. a. Use the Triangle Rule for adding vectors to explain why \(|\mathbf{u}+\mathbf{v}| \leq|\mathbf{u}|+|\mathbf{v}| .\) This result is known as the Triangle Inequality. b. Under what conditions is \(|\mathbf{u}+\mathbf{v}|=|\mathbf{u}|+|\mathbf{v}| ?\)

Compute the indefinite integral of the following functions. $$\mathbf{r}(t)=t e^{t} \mathbf{i}+t \sin t^{2} \mathbf{j}-\frac{2 t}{\sqrt{t^{2}+4}} \mathbf{k}$$

Diagonals of a parallelogram Consider the parallelogram with adjacent sides \(\mathbf{u}\) and \(\mathbf{v}\) a. Show that the diagonals of the parallelogram are \(\mathbf{u}+\mathbf{v}\) and \(\mathbf{u}-\mathbf{v}\) b. Prove that the diagonals have the same length if and only if \(\mathbf{u} \cdot \mathbf{v}=0\) c. Show that the sum of the squares of the lengths of the diagonals equals the sum of the squares of the lengths of the sides.

Consider the curve \(\mathbf{r}(t)=(a \cos t+b \sin t) \mathbf{i}+(c \cos t+d \sin t) \mathbf{j}+(e \cos t+f \sin t) \mathbf{k}\) where \(a, b, c, d, e,\) and \(f\) are real numbers. It can be shown that this curve lies in a plane. Assuming the curve lies in a plane, show that it is a circle centered at the origin with radius \(R\) provided \(a^{2}+c^{2}+e^{2}=b^{2}+d^{2}+f^{2}=R^{2}\) and \(a b+c d+e f=0\).

Let \(\mathbf{u}(t)=\left\langle 1, t, t^{2}\right\rangle, \mathbf{v}(t)=\left\langle t^{2},-2 t, 1\right\rangle\) and \(g(t)=2 \sqrt{t}\). Compute the derivatives of the following functions. $$\mathbf{v}(g(t))$$

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