# Difference between revisions of "ApCoCoA-1:Num.EigenValues"

 This article is about a function from ApCoCoA-1.

## Num.EigenValues

Computes the eigenvalues of a matrix.

### Syntax

```Num.EigenValues(A:MAT):MAT
```

### Description

Please note: The function(s) explained on this page is/are using the ApCoCoAServer. You will have to start the ApCoCoAServer in order to use it/them.

This function computes the approximate complex eigenvalues of the matrix A.

• @param A A quadratic matrix with rational entries.

• @return The return value is a matrix with two rows. Each column of this matrix represents one approximate complex eigenvalue of A, i.e. the first entry of a column is the real part and the second entry of the same column is the imaginary part of one complex eigenvalue.

#### Example

```Use P::=QQ[x,y,z];

A:=Mat([[1,2,7,18],[2,4,9,12],[23,8,9,10],[7,5,3,2]]);
Dec(Num.EigenValues(A),3);
-- CoCoAServer: computing Cpu Time = 0.015
-------------------------------
Mat([
["28.970", "-13.677", "0.353", "0.353"],
["0", "0", "3.051", "-3.051"]
])
-------------------------------

```