Flashcards in Final Exam Deck (14)

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1

## How do you calculate a vector answer

### Horizontal Times Vertical (add each digits products together)

2

## What is the formula for determining the size of the new matrix

### Rows in #1 = Columns in #2

3

## How do you determine if multiplying a matrix is possible?

### Columns in #1 = Rows in #2

4

## How do you multiply a 2x2 or 3x2 or 3x3 Matrix

### Take the horizontal row in #1 and multiply by vertical column in #2 .... until all numbers are populated

5

## What is the formula for the Inverse

###
1

___ X adj (A)

det(A)

6

## What is the formula for the determinant of a 2x2

### ad-bc

7

## What is the formula for a determinant of a 3x3

### Build 3 row, 5 column table by repeating the first 2 columns

8

## How do you know if a determinant isn't possible?

### ad-bc = 0

9

##
How do you build A using Cramers rule in a 2 exponent equation?

ex: 4x + 3y = -23

3x - 5y = 19

###
[ 4 3]

[ 3 5]

A = x (eq1) , y (eq 1)

x (eq2) , y (eq1)

10

##
How do you build A-1 using Cramers rule in a 2 exponent equation?

ex: 4x + 3y = -23

3x - 5y = 19

###
[-23 3]

[ 19 -5]

A-1 = Prod. eq 1, Y (eq 1)

Prod. eq 2, Y (eq 2)

11

##
How do you build A2 using Cramers rule in a 2 exponent equation?

ex: 4x + 3y = -23

3x - 5y = 19

###
[4 -23]

[3 19]

A2 = X from both eq, product from both eq.

12

## How do you finish using Cramers rule once the tables have been populated?

###
Find the determinants, then,

Find the X and Y values by dividing the determinants

13

## How do you find an X value using a determinate with cramers rule?

###
X = Det A-1

Det A

14