Hello, I am trying to solve the equation when ceta is the unknown using SymPy(Introduction - SymPy 1.11 documentation)

```
import math
from sympy.solvers import solve
from sympy import Symbol
ceta = Symbol('ceta')
sigmax = 1.0;
sigmay = 6.0;
pw = 5.0;
expr = sigmax+sigmay-2*(sigmax-sigmay)*math.cos(2*ceta)-pw
solution=solve(expr, ceta)
```

Thank you