Mathematical Models

Question 1

how to multiply matrices?

Answer 1

1. check to see if you can multiply by making there are the same number of rows in one as columns in the other
2. take the value of the first row and column and multiply that value by the value by the 1nd column and then the 2nd and keep going
3. multiply 1st row of A by 1st column of B and then by 2nd column of B and keep going and then go onto 2nd row

Question 2

how to calculate adjoint ( for bigger than square matrices

Answer 2

1. calculate determinant of all the values in the matrix
2. create an adjoint matrix by placing all of these values into the plus and minuses matrix
3. transpose this matrix

Question 3

how to calculate inverse of 2x2 matrix

Answer 3

calculate determinant first
diagonally swap a and d around and b and c and put negative sings in front of b and c
equation on pinboard.

Question 4

how to calculate inverse of bigger square matrices

Answer 4

A^(-1) = 1/det(A) * adj(A)

Question 5

how to determine determinant of bigger matrices

Answer 5

1. use the values in the first row only
2. use the minuses and plus matrices to determine whether its a positive or negative value.
3. calculate determinant of all of those values and add them up