Math Problem Statement

Consider the two vectors v = [1, 1] and w = [3, 1]. Adjust the scalars a and b such that the linear combination a*v + b*w equals the target vector [9.4, 6.4]. What are the values of a and b?

Solution

The problem involves finding scalars aa and bb such that the linear combination of the given vectors v=[11]\mathbf{v} = \begin{bmatrix} 1 \\ 1 \end{bmatrix} and w=[31]\mathbf{w} = \begin{bmatrix} 3 \\ 1 \end{bmatrix} equals the target vector [9.46.4]\begin{bmatrix} 9.4 \\ 6.4 \end{bmatrix}.

Step-by-Step Solution:

  1. Define the linear combination: The linear combination of vectors v\mathbf{v} and w\mathbf{w} is given by: av+bw=a[11]+b[31].a\mathbf{v} + b\mathbf{w} = a\begin{bmatrix} 1 \\ 1 \end{bmatrix} + b\begin{bmatrix} 3 \\ 1 \end{bmatrix}.

  2. Expand the combination: This can be rewritten as: [a+3ba+b].\begin{bmatrix} a + 3b \\ a + b \end{bmatrix}.

  3. Set up the system of equations: We need this to equal the target vector: [a+3ba+b]=[9.46.4].\begin{bmatrix} a + 3b \\ a + b \end{bmatrix} = \begin{bmatrix} 9.4 \\ 6.4 \end{bmatrix}. This gives us two equations: a+3b=9.4,a + 3b = 9.4, a+b=6.4.a + b = 6.4.

  4. Solve the system: Subtract the second equation from the first: (a+3b)(a+b)=9.46.4,(a + 3b) - (a + b) = 9.4 - 6.4, 2b=3,2b = 3, b=1.5.b = 1.5.

    Substitute b=1.5b = 1.5 into the second equation: a+1.5=6.4,a + 1.5 = 6.4, a=4.9.a = 4.9.

Final Answer:

The scalars are a=4.9a = 4.9 and b=1.5b = 1.5.

Would you like more details or have any questions?

Here are some related questions you might find helpful:

  1. What is the geometric interpretation of linear combinations?
  2. How do different values of aa and bb affect the resulting vector?
  3. Can vectors v\mathbf{v} and w\mathbf{w} span all of R2\mathbb{R}^2?
  4. What is the significance of solving systems of linear equations in vector spaces?
  5. How can you determine if two vectors are linearly independent?

Tip: Understanding the geometric representation of vectors helps in visualizing the effect of different scalar values on vector combinations.

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Math Problem Analysis

Mathematical Concepts

Linear Combinations
Vector Spaces
Systems of Linear Equations

Formulas

Linear combination: a*v + b*w
System of equations: a + 3b = 9.4, a + b = 6.4

Theorems

Linear Independence
Span of Vectors in R^2

Suitable Grade Level

Grades 10-12