$$\left(\begin{matrix}3 \ 2\end{matrix}\right)$$what's the value of this, and can you give an example what this can describe? I believe it is used in probabilities to describe possible combinations...

Question

rsadhvika · Answer

its just a matrix with one column
a matrix is just an entity, it wont have any value as such

anonymous · Answer

it is called "3 over 2"

rsadhvika · Answer

since it has only one column, we can call it a  "column vector"

rsadhvika · Answer

no, u cant calle it 3 over 2

rsadhvika · Answer

you may just say that, the elements in column are 3 and 2

blockcolder · Answer

Maybe it's a combination?

anonymous · Answer

yes how do combinations work?

rsadhvika · Answer

It can describe a point in two dimensions

blockcolder · Answer

Like, how to choose 2 people from a group of 3?

rsadhvika · Answer

\left(\begin{matrix}3 \ 2\end{matrix}ight)

u intend it to be a matrix wid that code above right ? @mathessentials

anonymous · Answer

no, I meant what is called "3 over 2", it is in round brackets as well

anonymous · Answer

and yes it is something like choose 2 people of 3

rsadhvika · Answer

ahh ok then its just a combination

3C2

blockcolder · Answer

Then you can use \binom{n}{k} and it will come out like this:
$$\binom{n}{k}$$

anonymous · Answer

@rsadhvika @blockcolder
I see, thanks
is there a reason it is called "binom" ???
$$\binom{3}{2}$$

blockcolder · Answer

It is read as "n choose k" and it is the number of ways you can choose k elements out of a set of n, where order of choosing is not an issue. For example, selecting 5 people out of a group of 20 to be part of your team.
It is called "binom" because another name for $\binom{n}{k}$ is binomial coefficients. These numbers appear in the expansion of (x+y)^n. Specifically, $\binom{n}{k}$ is the coefficient of $x^ky^{n-k}$ in (x+y)^n.