# How do you write matrices on Socratic?

##### 3 Answers
Mar 4, 2015

Hello!

I'll show you first how to write matrices without the programmed version, so you know what to type between the .

Let's say we want to make this generic matrix: You would type ((a,b),(c,d))
So you put each row in a set of parenthesis and seperate your values from left to right with commas.. When you want to start a new row, you close the parenthesis, add a comma, and start a new set of parenthesis following the same process.

Let's put the a  on either side of ((a,b),(c,d)) to create our matrix:

$\left(\begin{matrix}a & b \\ c & d\end{matrix}\right)$

You can now make the matrix as big as you would like with whatever numbers you like. For example, I can type this within two number signs ((-1,0,112),(0,-4,45),(-6,-6/5,-3)) to get:

$\left(\begin{matrix}- 1 & 0 & 112 \\ 0 & - 4 & 45 \\ - 6 & - \frac{6}{5} & - 3\end{matrix}\right)$

Apr 30, 2015

I didn't want to alter Sally's excellent answer, so I posted this as a separate answer.

I want to show you some variations of the classic matrix format. You can write

• Without the hashtags

[ (x, y, z), (1, 2, 3), (4, 5, 6) ]

• With the hashtags

$\left[\begin{matrix}x & y & z \\ 1 & 2 & 3 \\ 4 & 5 & 6\end{matrix}\right]$

• Without the hashtags

| (x, y, z), (1, 2, 3), (4, 5, 6) |

• With the hashtags

$| \left(x , y , z\right) , \left(1 , 2 , 3\right) , \left(4 , 5 , 6\right) |$

• Without the hashtags

|| (x, y, z), (1, 2, 3), (4, 5, 6) ||

• With the hashtags

$| | \left(x , y , z\right) , \left(1 , 2 , 3\right) , \left(4 , 5 , 6\right) | |$

Found the last two while looking for ways to write definitions by cases :D

• Without the hashtags

{ (x, y, z), (1, 2, 3), (4, 5, 6) :}}

• With the hashtags

{ (x, y, z), (1, 2, 3), (4, 5, 6) :}}

• Without the hashtags

{: (x, y, z), (1, 2, 3), (4, 5, 6) :}

• With the hashtags

$\left.\begin{matrix}x & y & z \\ 1 & 2 & 3 \\ 4 & 5 & 6\end{matrix}\right.$

Here's what I've got too.

#### Explanation:

Another type of brackets

(:(x,y,z),(a,b,c),(1,2,3):) or <<(x,y,z),(a,b,c),(1,2,3)>>

$\left\langle\begin{matrix}x & y & z \\ a & b & c \\ 1 & 2 & 3\end{matrix}\right\rangle$

You can mix left and right sides independently (not including |)

[(x,y,z),(a,b,c),(1,2,3):)

$\left[\begin{matrix}x & y & z \\ a & b & c \\ 1 & 2 & 3\end{matrix}\right\rangle$

{(x,y,z),(a,b,c),(1,2,3))

$\left\{\begin{matrix}x & y & z \\ a & b & c \\ 1 & 2 & 3\end{matrix}\right)$

{:(x,y,z),(a,b,c),(1,2,3):}}

{:(x,y,z),(a,b,c),(1,2,3):}}

You can leave empty cells

((,y,),(a,,c),(,2,))

$\left(\begin{matrix}\null & y & \null \\ a & \null & c \\ \null & 2 & \null\end{matrix}\right)$

((x,,z),(,b,),(1,,3))

$\left(\begin{matrix}x & \null & z \\ \null & b & \null \\ 1 & \null & 3\end{matrix}\right)$

Nonsquare and nested matrices are also possible.

$\left(\begin{matrix}x & y & z \\ a & b & \left(\begin{matrix}x & y & z \\ a & b & c \\ 1 & 2 & 3\end{matrix}\right) \\ 1 & 2 & 3\end{matrix}\right)$