Matrices

Question 1

How can you add matrices

Answer 1

Only if they are the same size
Add the elements at their corresponding positions

Question 2

How can you scale a matrix

Answer 2

Multiply each element in the matrix by some scale factor

Question 3

Matrix multiplication

Answer 3

Only possible if there are as many rows in matrix A as there comumns in matrix B

Question 4

Identity matrix

Answer 4

A square matrix consisting of a diagonal 1 and 0’s everywhere else

Question 5

When can a matrix be inverted

Answer 5

If it is square and and has a non-zero detriment

Question 6

How to calculate the inverse of a matrix

Answer 6

Find the detriment:
1 / (a x d) - (b x c)

Then find the adjugate:
swap top left and bottom right elements, then flip signs of top right and bottom left

Finally, multiply the adjugate by the detriment