Math Problem Statement

Given vectors u = (2, 3) and v = (1, 5): (a) Determine t = u + v. (b) Find vector p such that it is orthogonal to vectors u and t.

Solution

From the image, the question deals with vector operations. Let's break down the problem:

Question Details:

  1. Given vectors:

    • u=(23)\mathbf{u} = \begin{pmatrix} 2 \\ 3 \end{pmatrix},
    • v=(15)\mathbf{v} = \begin{pmatrix} 1 \\ 5 \end{pmatrix}.
  2. Tasks: a) Determine t=u+v\mathbf{t} = \mathbf{u} + \mathbf{v}.
    b) Find a vector p\mathbf{p} such that it is orthogonal to both u\mathbf{u} and t\mathbf{t}.


Solution:

(a) Determine t\mathbf{t}:

t=u+v=(23)+(15)=(2+13+5)=(38).\mathbf{t} = \mathbf{u} + \mathbf{v} = \begin{pmatrix} 2 \\ 3 \end{pmatrix} + \begin{pmatrix} 1 \\ 5 \end{pmatrix} = \begin{pmatrix} 2 + 1 \\ 3 + 5 \end{pmatrix} = \begin{pmatrix} 3 \\ 8 \end{pmatrix}.

So, t=(38)\mathbf{t} = \begin{pmatrix} 3 \\ 8 \end{pmatrix}.


(b) Find vector p\mathbf{p} orthogonal to u\mathbf{u} and t\mathbf{t}:

A vector p=(xy)\mathbf{p} = \begin{pmatrix} x \\ y \end{pmatrix} is orthogonal to u\mathbf{u} and t\mathbf{t} if: up=0andtp=0.\mathbf{u} \cdot \mathbf{p} = 0 \quad \text{and} \quad \mathbf{t} \cdot \mathbf{p} = 0. Here, the dot product is defined as: ab=a1b1+a2b2.\mathbf{a} \cdot \mathbf{b} = a_1b_1 + a_2b_2.

  1. Orthogonal to u\mathbf{u}: \mathbf{u} \cdot \mathbf{p} = 2x + 3y = 0. \tag{1}

  2. Orthogonal to t\mathbf{t}: \mathbf{t} \cdot \mathbf{p} = 3x + 8y = 0. \tag{2}

We now solve this system of linear equations:

  • From (1): 2x+3y=0    x=32y.2x + 3y = 0 \implies x = -\frac{3}{2}y.
  • Substituting x=32yx = -\frac{3}{2}y into (2): 3(32y)+8y=0    92y+8y=0    72y=0.3\left(-\frac{3}{2}y\right) + 8y = 0 \implies -\frac{9}{2}y + 8y = 0 \implies \frac{7}{2}y = 0. Thus, y=0y = 0, and substituting back, x=0x = 0.

This suggests that there is an issue with orthogonality across u\mathbf{u} and t\mathbf{t}, since their span covers the 2D space. Hence, no non-zero vector orthogonal to both exists in 2D.


Would you like further assistance or clarifications on this? Here are 5 follow-up questions:

  1. How does orthogonality relate to the span of vectors in 2D or higher dimensions?
  2. Could you explain why a solution might not exist for orthogonality constraints in specific cases?
  3. How can cross products help to find orthogonal vectors in 3D?
  4. What does the geometric interpretation of uv=0\mathbf{u} \cdot \mathbf{v} = 0 imply?
  5. How do you verify solutions of systems of equations like these?

Tip: Always confirm the independence of given vectors before solving

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Math Problem Analysis

Mathematical Concepts

Vector addition
Orthogonality
Dot product

Formulas

Vector addition: t = u + v
Dot product: a·b = a1*b1 + a2*b2

Theorems

Orthogonality: Two vectors are orthogonal if their dot product is zero.

Suitable Grade Level

Grades 10-12