# Square root of a fraction

I have the following variable and function:

```
var('r')
f = function('f')(r)
```

with an equation given by:

```
eq = sqrt(-1/(f^2*sin(r)^2))-1/sqrt(-f^2*sin(r)^2)
```

which, in LaTeX expression, looks like:

\begin{equation} \sqrt{-\frac{1}{f\left(r\right)^{2} \sin\left(r\right)^{2}}} - \frac{1}{\sqrt{-f\left(r\right)^{2} \sin\left(r\right)^{2}}} \end{equation}

In principle, this should be equal to zero. However,

```
bool(eq==0)
```

gives me `False`

. I have tried with `.simplify_full()`

and following the suggestion in here, I have used `._sympy_().simplify()`

:

```
eq = eq._sympy_().simplify()
bool(eq==0)
```

but I still get `False`

. Am I missing something?