matrices

Question 1

column

Answer 1

line of numbers vertically

Question 2

row

Answer 2

line of numbers vertically

Question 3

element

Answer 3

each number or variable of a matrix

Question 4

how do you name a matrix

Answer 4

row number then column number

Question 5

column matrix

Answer 5

matrix with one column

Question 6

trace

Answer 6

sum of numbers of the leading diagonal in a matrix

Question 7

square matrix

Answer 7

matrix with same number of rows and columns

Question 8

row matrix

Answer 8

matrix with one row

Question 9

diagonal matrix

Answer 9

only has non zero values along the leading diagonal

Question 10

unit matrix

Answer 10

only has non zero values along the leading diagonal and that value is a one

Question 11

upper triangular matrix

Answer 11

only has non zero values along leading diagonal and above

Question 12

lower triangular matrix

Answer 12

only has non zero values below the leading diagonal

Question 13

transpose

Answer 13

turn rows into columns and columns into rows

Question 14

how do you do addition with matrices

Answer 14

add each element in the matrices

Question 15

do matrices that you are adding need to have the same number of elements

Answer 15

yes

Question 16

how do you do subtraction with matrices

Answer 16

subtract each element in the matrix with the minus sign from the other matrix

Question 17

how do you multiply matrices

Answer 17

go through each row in the column matrix and multiply by the rows in the other matrix (see video for more information)

Question 18

does the number of columns in the first matrix have to be equal to the number of rows in the second matrix when multiplying

Answer 18

yes

Question 19

how do you find the size of the matrix after multiplication

Answer 19

number of rows in first matrix and number of columns in the second matrix (see lecture for how to multiply matrices)

Question 20

determinant

Answer 20

written with modulus sign is a scalar value found by multiplying the values on the leading diagonal together and then subtracting the result of the multiplication of the numbers in the other diagonal

Question 21

minor

Answer 21

removing rows and columns to make finding a determinant possible

Question 22

how are the signs found when finding a determinant in a matrix

Answer 22

the signs alternate

Question 23

how do you find the inverse of a matrix

Answer 23

1. find determinant
2. create matrix of minors by replacing each element with the determinant found when it is a minor
3. create the matrix of cofactors by alternating plus and minus signs in the matrix
4. find adjoint by transposing the matrix of cofactors
5. divide adjoint by determinant

Question 24

how to divide matrices

Answer 24

multiply the matrix you are dividing with the inverse of the other matrix