All Linear Algebra Resources
Example Questions
Example Question #201 : Operations And Properties
Consider the following set of vectors
Is the the set linearly independent?
No
Yes
Not enough information
No
The vectors have dimension 3. Therefore the largest possible size for a linearly independent set is 3. But there are 4 vectors given. Thus, the set cannot be linearly independent and must be linearly dependent
Another way to see this is by noticing that can be written as a linear combination of the other vectors:
Example Question #281 : Linear Algebra
In a vector space with dimension 5, what is the maximum number of vectors that can be in a linearly independent set?
Five
Not enough information
There is no limit
Two
Ten
Five
The dimension of a vector space is the maximum number of vectors possible in a linearly independent set. (notice you can have linearly independent sets with 5 or less, but never more than 5)
Example Question #282 : Linear Algebra
What is the dimension of the space spanned by the following vectors:
Five
Six
Three
One
Not enough information
Three
Since there are three linearly independent vectors, they span a 3 dimensional space.
Notice that the vectors each have 5 coordinates to them. Therefore they actually span a 3 dimensional subspace of a 5 dimensional space.
Example Question #204 : Operations And Properties
What is the dimension of the space spanned by the following vectors:
Five
Not enough information
Three
One
Two
Three
Since there are three linearly independent vectors, they span a 3 dimensional space.
Notice that the vectors each have 5 coordinates to them. Therefore they actually span a 3 dimensional subspace of a 5 dimensional space.
Example Question #205 : Operations And Properties
True or False: If a matrix has linearly independent columns, then .
True
False
True
Since is a matrix, . Since has three linearly independent columns, it must have a column space (and hence row space) of dimension , causing by the definition of rank. Hence.
Example Question #21 : Linear Independence And Rank
If , what is ?
None of the other answers
is equal to the number of linearly independent columns of . The first and third columns are the same, so one of these columns is redundant in the column space of . The second column evidently cannot be a multiple of the first, since the second has two 's, and the first has none. Hence .
Example Question #21 : Linear Independence And Rank
Consider the polynomials
True or false: these four polynomials form a basis for , the set of all polynomials with degree less than or equal to 3.
False
True
True
A test to determine whether these matrices form a basis is to set up a matrix with each row comprising the coefficients of one polynomial, and performing row reductions until the matrix is in row-echelon form. is a vector space of dimension 4, so these four polynomials will form a basis if and only if the resulting matrix has rank 4. The initial matrix is:
Perform the following row operations:
The matrix is now in row-echelon form. Each row has a leading 1, so the matrix has rank 4, the dimension of . It follows that the given polynomials comprise a basis of .
Example Question #202 : Operations And Properties
Consider the polynomials:
True or false: these four polynomials form a basis for , the set of all polynomials with degree less than or equal to 3.
False
True
False
Elements of a vector space form a basis if the elements are linearly independent and if they span the space - that is, every element in that space can be uniquely expressed as the sum of the elements.
A test to determine whether these matrices form a basis is to set up a matrix with each row comprising the coefficients of one polynomial, and performing row reductions until the matrix is in row-echelon form. is a vector space of dimension 4, so these four polynomials will form a basis if and only if the resulting matrix has rank 4. The initial matrix is:
Perform the following row operations:
The matrix is now in row-echelon form. There is a row of zeroes at the bottom, so the rank of the matrix is 3. Therefore, the four polynomials are not linearly independent, and they do not form a basis for .
Example Question #21 : Linear Independence And Rank
, , , and .
True or false: these four matrices form a basis for the vector space , the set of matrices.
False
True
True
A test to determine whether these matrices form a basis is to set up a matrix with each row comprising the coefficients of one polynomial, and performing row reductions until the matrix is in row-echelon form. is a vector space of dimension 4, so these four polynomials will form a basis if and only if the resulting matrix has rank 4. The initial matrix is:
Perform the following row operations:
The matrix is now in row-echelon form. Each row has a leading 1, so the matrix has rank 4, the dimension of . It follows that the four matrices , , , and comprise a basis of .
Example Question #21 : Linear Independence And Rank
In a 5 dimensional vector space, what is the maximum number of vectors you can have in a linearly dependent set?
No limit
Five
Zero
Ten
One
No limit
Linearly dependent sets have no limit to the number of vectors they can have.
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