Adding and Subtracting Matrices
What are the dimensions of this Matrix
[[x,x],[x,x]]
2 X 2 Matrix
What is the one thing that needs to be true in order to multiply matrices?
The inner numbers of the dimension needs to be the same.
What type of shape does the matrix need to be in order to have a determinant?
A square matrix
i = sqrt(-1)
What does i^2 equal
i^2=-1
When can you add or subtract matrices?
When they have the same dimensions.
2[[8,-2],[8,-2]]
[[16,-4],[16,-4]]
What is the formula for finding a 2 X 2 matrix
ad-bc
Write a complex number
a+bi
4i(3+7i)
(12i-28)
Add
[[7,12],[5,8]] + [[3,9],[10,11]]
[[10,21],[15,19]]
[[7,8]]times[[1],[2]]
[[23,]]
Find the determinant of
[[3,6],[1,9]]
21
(3 -4i)+(9-2i)
(12-6i)
(1+3i)(1+3i)
(-8+6i)
Subtract
[[-2,-1],[-5,9]]-[[-6,0],[4,10]]
[[4,-1],[-9,-1]]
[[3,1],[4,3]] times [[1,4],[2,7]]
[[5,19],[10,37]]
Find the determinant of
[[-10,9],[-2,0]]
18
(-8-2i)-(3+9i)
(-11-11i)
(7i)(6i)times-2
84
Subtract
[[3,7],[8x,9x]] -[[10x,2,1,0],[1,12,3,1]]
Undefined
[[-3,5],[-1,3]] times [[-4x,x],[2x,-3x]]
[[22x,-18x],[10x,-10x]]
Find the determinant
[[2,1,3],[4,-2,1],[5,3,-1]]
73
(-5-9i)-(-5+9)
(-9-9i)
(-2i)(4i)(9+3i)
(72+24i)
A small cafe keeps track of its daily sales for coffee and tea over two days. The sales are recorded as matrices where each row represents a day, and each column represents a product.
The sales matrix is:
[[50,30],[60,40]]
The profit per item is given as:
[[2],[1.5]]
2 is the profit for coffee, and 1.5 is the profit for tea.
How much profit did the cafe make on Day 1 and Day 2?
Day 1: $145
Day 2: $180