## 3. Types

### a. Vector

A vector matrix is a single dimension matrix with either one row or one column.

### b. Square

A square matrix is has the same number of rows as columns: _{m}**[A]**_{m}

A matrix element is identified using the lower case version of the matrix name. It is preceded by its row location and followed by its column location: element _{3}a_{2} is in the third row and second column. The elements of the **[A]** matrix are:

### c. Diagonal Matrix

A diagonal matrix is square with non-zero elements along one diagonal and zeros in the off-diagonal elements.

### d. Identity Matrix

An identity matrix is a special diagonal matrix where the upper-left to lower-right diagonal elements are all equal to one.

An identity matrix is generally identified as **[****I]**.

### e. Symmetric Matrix

A symmetric matrix is a square matrix whose elements are mirrored about its diagonal.