# Full simplification of power doesn't work

```
x, a =SR.var('x a')
Uf1= x^a
ar1_x=diff(Uf1, x).full_simplify()
ar1_xx=diff(Uf1, x,2)
raar1 = -diff(Uf1, x,2)/diff(Uf1, x).full_simplify()
show(LatexExpr("U^{'}(x) ="+latex(ar1_x)))
show(LatexExpr("U^{''}(x) ="+latex(ar1_xx)))
show(LatexExpr("R_a(x) ="+latex(raar1)))
```

Why raar1 is not fully simplified ?