Why a Vector x Satisfying Ax=0 is Normal to a Plane

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SUMMARY

In the discussion, it is established that for a 2 by 3 matrix A with nonzero, nonparallel row vectors v1 and v2 in R3, any nonzero vector x satisfying the equation Ax = 0 is a normal vector to the plane spanned by v1 and v2. This is because the equation Ax = 0 implies that the dot product of x with each row vector (C and D) is zero, indicating that x is orthogonal to both vectors, thus confirming its status as a normal vector to the plane defined by v1 and v2.

PREREQUISITES
  • Understanding of linear algebra concepts, specifically vector spaces.
  • Knowledge of matrix operations, particularly the multiplication of matrices and vectors.
  • Familiarity with the concept of normal vectors in geometry.
  • Basic understanding of the dot product and its geometric interpretation.
NEXT STEPS
  • Study the properties of normal vectors in relation to planes in R3.
  • Learn about the implications of the null space of a matrix, specifically in the context of Ax = 0.
  • Explore the geometric interpretation of the dot product and its role in determining orthogonality.
  • Investigate the relationship between row vectors of a matrix and the span of a vector space.
USEFUL FOR

Students of linear algebra, educators teaching vector geometry, and anyone seeking to understand the relationship between matrices and geometric interpretations in R3.

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Homework Statement



b. Let A be a 2 by 3 matrix whose rows, v1 and v2 are nonzero, nonparallel vectors in R3. Why is any nonzero vector x that satisfies the equation Ax = 0 a normal vector for the plane spanned by the vectors v1 and v2? Explain your response.

Homework Equations





The Attempt at a Solution


I have no idea where to begin. Please help.
 
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Hint: If you call the row vectors of the matrix C and D, What does Ax = 0 tell you about the dot product of C and D with x?
 

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