Question

Really need help... Honestly, I am so lost. .__.

http://tinypic.com/r/10fq2w6/9

Answer 1

you wrote `2 x 3` but you have it the other way around. It should be `3 x 2`

the first number is the number of rows. In this case, there are 3 rows
The second number is the number of columns, which is 2

Answer 2

Ohhh! I see now, on that first one! 3 x 2 I got it backwards

Answer 3

if you wanted a 2 x 3 matrix, then here's one example

\[\Large \begin{bmatrix}1 & 9 & 14\\3 & 2 & 1\end{bmatrix}\]

this has 2 rows, 3 columns

Answer 4

I am not sure of the second one... I thought it would be 3 x 3?

Answer 5

for #2, the notation `D12` means "the element in row 1, column 2"

D12 is sometimes written as \(\LARGE D_{1,2}\)

Answer 6

Uhhh... I don't get it... > >' I don't get what it is asking for the answer...

Answer 7

Let's say we had this matrix as an example


\[
\Large A = \begin{bmatrix}
\Large 2 & 3\\
\Large 1 & 5\\
\Large 7 & 9
\end{bmatrix}
\]

Answer 8

The ones in the second question look differently than that. They are in like... um...
0 -2 3
1 -5 2

Answer 9

I'm going to highlight in red, the element \(\LARGE A_{2,1}\)


\[
\Large A = \begin{bmatrix}
\Large 2 & 3\\
\Large {\color{red}{1}} & 5\\
\Large 7 & 9
\end{bmatrix}
\]


Notice how this red element is in row 2, column 1

Answer 10

now onto row 1, column 2

marked in blue

\[
\Large A = \begin{bmatrix}
\Large 2 & \color{blue}{3}\\
\Large {\color{red}{1}} & 5\\
\Large 7 & 9
\end{bmatrix}
\]

we denote this as \(\LARGE A_{1,2}\)

Answer 11

Is this making sense?

Answer 12

Not really. :C I am sorry...

Answer 13

in my example, what numbers are in row 3

Answer 14

Ummm 7 and 9?

Answer 15

7 is in column 1, 9 is in column 2

agreed?

Answer 16

Umm.. Yes! Yes they are :D

Answer 17

I just don't get the D12... 1, 2? Row 1, column 2...? That would be number 1 I think

Answer 18

so the notation \(\LARGE A_{3,1}\) refers to the address of the number at row 3, column 1

which is 7 in this case. So we say \(\LARGE A_{3,1} = 7\) since "7" is at row 3, column 1

Answer 19

D12 means you look at row 1, then find the number that is in column 2. Whatever that number is, that's your answer

Answer 20

I tried entering 1 and it says it is incorrect so I put it as D12 = 1 and then tried D1,2 = 1 and it's not working as the answer... I am confused

Answer 21

think of a city block of 6 houses

their addresses are D11, D12, etc as shown below