1 | initial version |

The problem does not come from the plotting function but from the fact that your functions `FF1`

, `FF2`

, `FF3`

cannot return numerical values because `Phi_1`

, `Phi_2`

and `Phi_3`

contain unevaluated integrals:

```
Phi_1
-2*integrate((w^2 - 1)/sqrt((4*w^6 + 7*sqrt(2)*w^3 - 4)*w), w)
```

You should probably use `numerical_integral`

instead of integrate and specify some integration bounds.

The case of the commented line worked because SageMath was capable to find an explicit primitive:

```
R=-I*w^2
Phi_1=((1-w^2)/R).integrate(w)
Phi_1
-I*w - I/w
```

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