Linear Algebra Chapters 1 & 2 Quiz
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Linear Algebra Chapters 1 & 2 Quiz

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@PatriLavender

Questions and Answers

Every matrix is row equivalent to a unique matrix in echelon form.

False

Every matrix is row equivalent to a unique matrix in reduced row echelon form.

True

Any system of n linear equations in n variables has at most n solutions.

False

If a system of linear equations has two different solutions, it must have an infinite number of solutions.

<p>True</p> Signup and view all the answers

If a system has no free variables, it has a single solution.

<p>False</p> Signup and view all the answers

If an augmented matrix [A b] is transformed into [C d] by elementary row operations, then the equations Ax = b and Cx = d have the same solutions.

<p>True</p> Signup and view all the answers

The equation Ax = 0 has the trivial solution if and only if there are no free variables.

<p>False</p> Signup and view all the answers

If A is an m x n matrix and the equation Ax = b is consistent for every b in R^m, then A has m pivot columns.

<p>True</p> Signup and view all the answers

If an n x n matrix A has n pivot positions, then the reduced echelon form of A is the n x n identity matrix.

<p>True</p> Signup and view all the answers

If Set U, V, W is linearly independent, then u, v, and w are not in R^2.

<p>True</p> Signup and view all the answers

If u and v are in R^m, then -u is in Span(u, v).

<p>True</p> Signup and view all the answers

If a system Ax = b has more than one solution, then so does the system Ax = 0.

<p>True</p> Signup and view all the answers

If an augmented matrix [A b] can be transformed by elementary row operations into reduced echelon form, then the equation Ax = b is consistent.

<p>False</p> Signup and view all the answers

If matrices A and B are row equivalent, then they have the same reduced echelon form.

<p>True</p> Signup and view all the answers

If an m x n matrix A has a pivot position in every row, then the equation Ax has a unique solution for each b in R^m.

<p>False</p> Signup and view all the answers

If 3x3 matrices A and B each have 3 pivot positions, then A can be transformed into B by elementary row operations.

<p>True</p> Signup and view all the answers

Study Notes

Echelon Forms

  • Every matrix is not row equivalent to a unique matrix in row echelon form; different echelon forms can exist due to row multiplication by nonzero constants.
  • Every matrix is row equivalent to a unique matrix in reduced row echelon form.

Linear Equations and Solutions

  • A system of ( n ) linear equations in ( n ) variables can have an infinite number of solutions, not just a maximum of ( n ).
  • If a linear system has two different solutions, it indicates the presence of at least one free variable, leading to infinitely many solutions.
  • A system without free variables can have at most one solution, but it may not guarantee a single solution.

Augmented Matrices and Row Operations

  • Transforming an augmented matrix ([A \ b]) to ([C \ d]) using elementary row operations keeps the solution set unchanged for systems ( Ax = b ) and ( Cx = d ).
  • The homogeneous equation ( Ax = 0 ) always possesses the trivial solution, independent of the presence of free variables.

Matrix Properties and Theorems

  • If an ( m \times n ) matrix ( A ) allows the equation ( Ax = b ) to be consistent for every ( b \in R^m ), then ( A ) must have ( m ) pivot columns.
  • A square ( n \times n ) matrix ( A ) possessing ( n ) pivot positions ensures its reduced echelon form is the identity matrix.
  • An ( r )-dimensional set composed of 3 vectors in ( R^2 ) cannot be linearly independent due to the limitation imposed by dimension.

Span and Linear Combinations

  • The vector (-u) belongs to ( \text{Span}(u, v) ) since it can be expressed as a linear combination: (-u = -1u + 0v).
  • A system that has multiple solutions for ( Ax = b ) implies that the associated homogeneous system ( Ax = 0 ) will also have multiple solutions.

Consistency and Reduced Echelon Form

  • An augmented matrix ([A \ b]) achieving reduced echelon form does not guarantee that ( Ax = b ) is consistent.
  • Row equivalent matrices ( A ) and ( B ) share the same reduced echelon form.

Unique Solutions and Pivot Positions

  • An ( m \times n ) matrix ( A ) containing a pivot position in every row does not automatically imply that ( Ax ) has a unique solution for each ( b \in R^m ).
  • If two ( 3 \times 3 ) matrices, ( A ) and ( B ), each feature three pivot positions, then they can be connected through elementary row operations.

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Test your knowledge on Linear Algebra concepts from Chapters 1 & 2 through this interactive flashcard quiz. Explore the uniqueness of echelon forms and the solutions of linear equations as you challenge yourself with these statements.

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