### simplify_trig and sorting, for example in fractions

The output of

```
show((1-cos(x)^2.simplify_trig())
show((cos(x)^2-1).simplify_trig())
```

is

```
sin(x)^2
cos(x)^2-1.
```

Even worse, the result of

```
(sin(x)^2/(1-cos(x)^2)).simplify().simplify_trig()
```

is

```
-(sin(x)^2/(cos(x)^2-1)
```

when it should be 1. Is there anyway to get sagemath to simplify trigonometric expressions more intelligently?