Matrix

Let a “matrix” be a Set of numbers ordered in a neat grid. Now we can manipulate a lot of numbers simultaneously. Interestingly enough, they are the solution to a lot of real world including machine learning and quantum mechanics.

Let’s make a new variable called $A$ .

Let $A$ be a matrix of size $m\times n$ where $m$ is the height of the matrix (how many rows it has) and $n$ is the width (how many columns it has).

Example:

\begin{gather*} A=\begin{pmatrix} 1 & 2 & 5 \\ 3 & 4 & 9 \end{pmatrix} \end{gather*}

See how $A$ is also a variable? In this case, $m=2, n=3$ as there are 2 rows and 3 columns.

We use matrices to represent multiple numbers because they have an equivalent in the real world. In this case, quantum states.