# MATLAB Programming/Advanced Topics/Numerical Manipulation/Simple matrix manipulation

## Contents

## Operations[edit]

### Squaring a matrix[edit]

a=[1 2;3 4]; a^2;

a^2 is the equivalent of a*a. To square each element:

```
a.^2
```

The period before the operator tells MATLAB to perform the operation element by element.

### Determinant[edit]

Getting the determinant of a matrix, requires that you first define your matrix, then run the function "det()" on that matrix, as follows:

a = [1 2; 3 4]; det(a) ans = -2

#### Symbolic Determinant[edit]

You can get the symbolic version of the determinant matrix by declaring the values within the matrix as symbolic as follows:

m00 = sym('m00'); m01 = sym('m01'); m10 = sym('m10'); m11 = sym('m11');

or

syms m00 m01 m10 m11;

Then construct your matrix out of the symbolic values:

m = [m00 m01; m10 m11];

Now ask for the determinant:

det(m) ans = m00*m11-m01*m10

### Transpose[edit]

To find the transpose of a matrix all you do is place an apostrophe after the bracket. Transpose- switch the rows and columns of a matrix.

Example:

a=[1 2 3] aTranspose=[1 2 3]'

or

```
b=a' %this will make b the transpose of a
```

when a is complex, the apostrophe means transpose and conjugate.

Example

a=[1 2i;3i 4]; a'=[1 -3i;-2i 4];

For a pure transpose, use .' instead of apostrophe.

## Systems of linear equations[edit]

There are lots of ways to solve these equations.

### Homogeneous Solutions[edit]

### Particular Solutions[edit]

### State Space Equations[edit]

## Special Matrices[edit]

Often in MATLAB it is necessary to use different types of unique matrices to solve problems.

### Identity matrix[edit]

To create an identity matrix (ones along the diagonal and zeroes elsewhere) use the MATLAB command "eye":

>>a = eye(4,3) a = 1 0 0 0 1 0 0 0 1 0 0 0

### Ones Matrix[edit]

To create a matrix of all ones use the MATLAB command "ones"

a=ones(4,3)

Produces:

a = 1 1 1 1 1 1 1 1 1 1 1 1

### Zero matrix[edit]

The "zeros" function produces an array of zeros of a given size. For example,

a=zeros(5,3)

Produces:

a = 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

This type of matrix, like the ones matrix, is often useful as a "background", on which to place other values, so that all values in the matrix except for those at certain indices are zero.