# How do you write matrices on Socratic?

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.

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