# simple(?) exponentiation simplification

I'm beginning with `sage`

. It sure looks great but I still have to understand what is the actual meaning of what I type in :-(

This is where I am currently stuck:

` ````
sage: simplify( (a/b)^c - (a^c)/(b^c) )
-a^c/b^c + (a/b)^c
```

I would have loved to get a nice clean **$0$**.
What do I need to tell `sage`

so that it sees that $(a/b)^c$ and $a^c/b^c$ are the same?

It's a bit the same problem that here : http://ask.sagemath.org/question/2718/why-abssinpin-is-not-simplified-by-sinpin-when-n2 And the answer is a bit the same... "The most one can say here is that Maxima doesn't "know" that sin(pi/n) is, in fact, positive. The assumptions framework in Maxima (and hence Sage) is acknowledged to be fairly weak."

? This is not the same thing. There isn't any particular reason that Sage (or any other system) should be asked to always expand such expressions; it could be arbitrarily computationally expensive to do so. Whereas when one *explicitly adds in an assumption*, it would be nice to have that happen (which is what the other question is about).