Matrices

Matrices

Matrices Summary

• A matrix is an arrangement of elements (usually numbers and letters) in rows and columns.

• The order or size of a matrix is the number of rows by the number of columns. e.g. 2 x 3 matrices has 2 rows and 3 columns.

• Matrices can be added or subtracted only if they are of the same order.

• To multiply matrices no. of columns in 1st matrix = no. of rows in 2nd matrix.

• A matrix X is SINGULAR if the determinant is o, i.e  $\left|X\right|\ or\ Det.\ X\ =0$  

• Inverse matrix, A $A^{-1}=\frac{1}{\left|A\right|}\times A\ adjoint$  
  

• To solve simultaneous equations, use the form  $X=A^{-1}B$  

Multiple Choice

What is the size or order of this matrix?

• 2 x 3

• 3 x 2

• 6 x 1

• 1 x 6

Multiple Select

Which of the following is true when multiplying matrices?

• no. of columns in 1st matrix = no of rows in 2nd matrix.

• multiply each row by each column.

• any two matrices can be multiplied

Multiple Choice

• A
• B
• C
• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

If |A| = 0, then A is

• zero matrix

• singular matrix

• non-singular matrix

• Identity matrix

Open Ended

What is the equation used for?

What part of the equation shows the determinant?

What part of the equation shows the adjoint?

Let's watch a short video on simultaneous equations using matrices

https://www.youtube.com/watch?v=SZqLjD6SD9E

That's a wrap

Remember the key is to practice!!!