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Example Questions
Example Question #31 : Reduced Row Echelon Form And Row Operations
True or false:
is an example of a matrix in row-echelon form.
False
True
True
A matrix is in row-echelon form if and only if it fits three conditions:
1) Any rows comprising only zeroes are at the bottom.
2) Any leading nonzero entries are 1's..
3) Each leading 1 is to the right of the one immediately above.
It can be seen that this matrix fits all three conditions, and is therefore in row-echelon form.
Example Question #31 : Reduced Row Echelon Form And Row Operations
True or false: is an example of a matrix in row-echelon form.
True
False
False
A matrix is in row-echelon form if and only if it fits three conditions:
1) Any rows comprising only zeroes are at the bottom.
2) Any leading nonzero entries are 1's..
3) Each leading 1 is to the right of the one immediately above.
All four rows have leading nonzero entries, but none of them are 1's. The matrix violates the conditions of a matrix in row-echelon form.
Example Question #31 : Reduced Row Echelon Form And Row Operations
Is the following matrix in reduced row echelon form? Why or why not.
Yes, the matrix is in reduced row echelon form
No, the matrix has nonzero elements
No, the matrix does not have all zero rows
No, the matrix has non zero lead entries
Yes, the matrix is in reduced row echelon form
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
This matrix meets all four of these criteria.
Example Question #31 : Reduced Row Echelon Form And Row Operations
Is the following matrix in reduced row echelon form? Why or why not.
Yes, the matrix is in reduced row echelon form
No, the matrix does not have an all zero row
No, the matrix has nonzero elements
No, the leading entry in the first row is not
No, the leading entry in the first row is not
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
For this matrix to be in reduced row echelon form, the leading entry in the first row would need to be , not .
Example Question #31 : Reduced Row Echelon Form And Row Operations
Is the following matrix in reduced row echelon form? Why or why not.
No, the matrix has nonzero terms
No, there is a nonzero row below an all zero row.
Yes, the matrix is in reduced row echelon form
Yes, the leading entries are all
No, there is a nonzero row below an all zero row.
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
For the matrix to be in reduced row echelon form, the and row would beed to be switched.
Example Question #32 : Reduced Row Echelon Form And Row Operations
Is the following matrix in reduced row echelon form? Why or why not.
No, the matrix has nonzero terms
No, there are no nonzero rows
No, there is a nonzero entry in the same column as a leading entry
Yes, the matrix is in reduced row echelon form
No, there is a nonzero entry in the same column as a leading entry
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
For the matrix to be in reduced row echelon form, the in the first row would need to be transformed into a using row operations.
Example Question #31 : Reduced Row Echelon Form And Row Operations
Used reduced row echelon form to solve the following system of equations
a
, ,
, ,
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
The first step in solving this system of linear equations is to represent this system as an augmented matrix.
We will use row operations to transform this matrix. There are three kinds of row operations that can be performed. Rows can be switched, a row can be multiplied by a constant and rows can be linearly combined ( where and are constants).
The first number in the row is , so no further calculation is needed.
We will make the first number in the row using the row operation
We now make the leading entry of the row using the row operation
Next we will make the first number in the row using the row operation
That operation also made the number in the row .
We now make the leading entry of the row using the row operation
The matrix is now in echelon form.
Next we change the term in the row to using the row operation
Next we change the term in the row to using the row operation
Last we change the term in the row to using the row operation
The matrix is now in reduced row echelon form and the last column is the solution to the system of equations.
, ,
Example Question #31 : Reduced Row Echelon Form And Row Operations
Used reduced row echelon form to solve the following system of equations
, ,
, ,
, ,
, ,
, ,
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
The first step in solving this system of linear equations is to represent this system as an augmented matrix
We will use row operations to transform this matrix. There are three kinds of row operations that can be performed. Rows can be switched, a row can be multiplied by a constant and rows can be linearly combined ( where and are constants).
Since the leading entry in the first row is , no further action is needed.
Next we will make the first number in the row using the row operation
We now make the leading entry of the row using the row operation
Next we will make the first number in the row using the row operation
The matrix is now in echelon form.
Next we change the term in the row to using the row operation
Next we change the term in the row to using the row operation
Last we change the term in the row to using the row operation
The matrix is now in reduced row echelon form and the last column is the solution to the system of equations.
, ,
Example Question #31 : Reduced Row Echelon Form And Row Operations
Used reduced row echelon form to solve the following system of equations
, ,
, ,
, ,
, ,
, ,
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
The first step in solving this system of linear equations is to represent this system as an augmented matrix.
We will use row operations to transform this matrix. There are three kinds of row operations that can be performed. Rows can be switched, a row can be multiplied by a constant and rows can be linearly combined ( where and are constants).
First we will make the first number in the row using the row operation
Next we will make the first number in the row using the row operation
We now make the leading entry of the row using the row operation
Next we will make the first number in the row using the row operation
Next we will make the number in the row using the row operation
We now make the leading entry of the row using the row operation
The matrix is now in echelon form.
Next we change the term in the row to using the row operation
Last we change the term in the row to using the row operation
The matrix is now in reduced row echelon form and the last column is the solution to the system of equations.
, ,
Example Question #31 : Reduced Row Echelon Form And Row Operations
Used reduced row echelon form to solve the following system of equations
, ,
, ,
, ,
, ,
, ,
A matrix is in reduced row echelon form if
- all nonzero rows are above any all zero rows
- the left most nonzero entry in each row (the leading entry) is .
- the leading entry is in a column to the right of the leading entry in the column above it
- all entries in a column below the leading entry are zero
The first step in solving this system of linear equations is to represent this system as an augmented matrix.
We will use row operations to transform this matrix. There are three kinds of row operations that can be performed. Rows can be switched, a row can be multiplied by a constant and rows can be linearly combined ( where and are constants).
The leading entry in the row needs to be , so we use the row operation to change it.
We will make the first number in the row using the row operation
We now make the leading entry of the row using the row operation
Next we will make the first number in the row using the row operation
Next we make the number in the row using the row operation
We now make the leading entry of the row using the row operation
The matrix is now in echelon form.
Next we change the term in the row to using the row operation
Next we change the term in the row to using the row operation
Last we change the term in the row to using the row operation
The matrix is now in reduced row echelon form and the last column is the solution to the system of equations.
, ,