# Calculation of symbolic eigenvalues

Hello, I am very new to Sage. In my first trial, I sought for eigenvalues of a symbolic matrix. However, Sage returns the following error: ArithmeticError: could not determine eigenvalues exactly using symbolic matrices; try using a different type of matrix via self.change_ring(), if possible

I have seen an example of eigenvalues of a symbolic matrix being calculated by Sage on another page. So I wonder what the problem is in this case. Below is my code:

```
var('s b')
A = matrix([[0,0,b,b,b,b,b,b,b,b],[s,0,0,0,0,0,0,0,0,0],[0,s,0,0,0,0,0,0,0,0],[0,0,s,0,0,0,0,0,0,0],[0,0,0,s,0,0,0,0,0,0],[0,0,0,0,s,0,0,0,0,0],[0,0,0,0,0,s,0,0,0,0],[0,0,0,0,0,0,s,0,0,0],[0,0,0,0,0,0,0,s,0,0],[0,0,0,0,0,0,0,0,s,0]]); A
A_evals = A.eigenvalues()
```

Many thanks for your support.