If you know that
, then you know right away

###
Otherwise, you can derive the same result. Let
, so that
.
is bounded, so we know
. For these values of
, we always have
.
So, recalling the Pythagorean theorem, we find

Then

as expected.
Answer:

Step-by-step explanation:
We want to simplify:

We rewrite as positive index to get:

This simplifies to

This will finally give us:

We cannot simplify further.
Hence the simplest form is 
The given information permits us to calculate the circumference (C) of the wheel as follows

Then (as you said correctly!) the same wheel will move

after 16 rolls.
I just did it on paper but hope that helps:)