I'm stuck on this one:

Use the Reciprocal Rule to verify that the Power Rule is valid for negative integers, that is,

for all positive integers n.

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Playing this out, I did this:

Next, I tried to restate the function like this:

and then I apply the Reciprocal Rule:

None of this is seems to be leading me anywhere helpful. Can anybody see where I might be going wrong or suggest another tack?

Thanks.