1. Operations with 2x2 matrices IB SL/HL www.ibmaths.com

2. Operations with matrices By the end of this lesson you should be able to: add and subtract matrices where possible multiply matrices where possible find the determinant of a 2x2 matrix find the inverse of a 2x2 matrix

3. Adding and subtracting 1. A+B 2. 3A-B 3. B-A 4. A+C 5. C+D Not possible

4. Multiplying 2 matrices together 1. AB 2. BA 3. AC 4. B 2 5. CD

5. The inverse and determinant of 2x2 matrices 1.2x2 matrix is written as A 2x2 matrix has a deteterminat ad-bc. 2.Swap a and d. Make b and c negative. 3.Multiply the matrix by the 1/determinat.

6. Explain why matrix B has no inverse. Find the determinant, which = 0. You can not divide the numbers by 0. This matrix is called a singular matrix as it has no inverse.

7. Now try some questions…. 1.A+B 2.AB 3.A -1 4. AD 5.B+D 6.BB -1 7.C -1 8.B -1 Not possible Not possible, as the determinant is 0.