Math Problem Statement

Given three vectors v1=(1,3,7),v2=(1,2,0),v3=(1,1,−7)v1=(1,3,7),v2=(1,2,0),v3=(1,1,−7). The vectors v1,v2,v3v1,v2,v3 are linearly independent.

Question 7Answer

True

False

Solution

To determine if the vectors v1=(1,3,7)\mathbf{v_1} = (1, 3, 7), v2=(1,2,0)\mathbf{v_2} = (1, 2, 0), and v3=(1,1,7)\mathbf{v_3} = (1, 1, -7) are linearly independent, we need to check whether the only solution to the equation

c1v1+c2v2+c3v3=0c_1 \mathbf{v_1} + c_2 \mathbf{v_2} + c_3 \mathbf{v_3} = \mathbf{0}

is c1=c2=c3=0c_1 = c_2 = c_3 = 0. This can be done by forming a matrix with v1\mathbf{v_1}, v2\mathbf{v_2}, and v3\mathbf{v_3} as columns and checking if the determinant is non-zero.

Step 1: Form the Matrix

1 & 1 & 1 \\ 3 & 2 & 1 \\ 7 & 0 & -7 \end{pmatrix}$$ ### Step 2: Calculate the Determinant $$\text{Det}(A) = 1 \cdot \begin{vmatrix} 2 & 1 \\ 0 & -7 \end{vmatrix} - 1 \cdot \begin{vmatrix} 3 & 1 \\ 7 & -7 \end{vmatrix} + 1 \cdot \begin{vmatrix} 3 & 2 \\ 7 & 0 \end{vmatrix}$$ $$\text{Det}(A) = 1 \cdot (2 \cdot -7 - 0 \cdot 1) - 1 \cdot (3 \cdot -7 - 1 \cdot 7) + 1 \cdot (3 \cdot 0 - 7 \cdot 2)$$ $$\text{Det}(A) = 1 \cdot (-14) - 1 \cdot (-21 - 7) + 1 \cdot (0 - 14)$$ $$\text{Det}(A) = -14 + 28 - 14 = 0$$ ### Step 3: Interpret the Result Since the determinant of the matrix $$A$$ is zero, this means the vectors $$\mathbf{v_1}$$, $$\mathbf{v_2}$$, and $$\mathbf{v_3}$$ are **not** linearly independent. Instead, they are linearly dependent. ### Final Answer - **False**: The vectors $$\mathbf{v_1}, \mathbf{v_2}, \mathbf{v_3}$$ are not linearly independent. Would you like more details on linear dependence, or do you have any other questions? --- Here are five follow-up questions you might consider: 1. What does it mean for vectors to be linearly dependent? 2. How can you determine the rank of a matrix formed by vectors? 3. What is the significance of a zero determinant in the context of vector independence? 4. How can the Gram-Schmidt process be used to orthogonalize vectors? 5. What are some real-world applications where linear independence is crucial? **Tip:** When vectors are linearly dependent, at least one of the vectors can be expressed as a linear combination of the others.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Vectors
Linear Independence
Determinants

Formulas

Determinant of a 3x3 matrix

Theorems

Criterion for linear independence

Suitable Grade Level

Grades 10-12