A matrix-style method for solving square systems of equations. We bust out a coefficient matrix, track down the determinant D
, and swap out each variable column for a constant column to get the new determinants Dx
. To solve for x
, divide Dx
. To solve for y
, divide Dy
. It's got more letters than a Chekhov play
, but it's super useful.
While it sounds like the name of some cheesy product from an "As Seen On TV" infomercial, it's actually a special number derived from a square matrix. It's useful to know sometimes, and it's written as |A
| = ad
for a 2 × 2 matrix.
Each number or variable inside the brackets of a matrix.
The matrix version of the number 1, i.e. the best matrix
. At least, it thinks that it's #1. More objectively speaking, it's a square matrix with a line of 1s running diagonal from upper-left to lower-right, with the rest of its entries as 0s.
Variables or constants arranged like a grid in rows and columns that together make up a rectangle. The rows
go across, and the columns
are vertical; they're like the columns in the Lincoln Memorial
. Here's a 2 × 2 matrix:
A constant multiplied throughout a matrix. That doesn't sound exciting, until everything in your matrix is suddenly a thousand times bigger. Hope you packed something good in there!
A matrix that has the same number of rows and columns. Literally, square matrices look square.
The matrix version of the number 0, i.e. a matrix filled with 0s. It can be any size, but try and be reasonable about it.