- #1

Gib Z

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Just as [tex]x^a-1 = (x-1)\sum_{n=0}^{a-1} x^n[/tex], is there a similar expansion for x^n - y^n?

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- Thread starter Gib Z
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- #1

Gib Z

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Just as [tex]x^a-1 = (x-1)\sum_{n=0}^{a-1} x^n[/tex], is there a similar expansion for x^n - y^n?

- #2

Hurkyl

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What happens if you divide by y^{n}?

- #3

Gib Z

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- #4

Hurkyl

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What's wrong with it? Once you're done simplifying, it's almost the same expression. Maybe you didn't multiply the y^n back in?

I get (x - y) sum_i x^i y^(n-1-i) .

I get (x - y) sum_i x^i y^(n-1-i) .

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- #6

Gib Z

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Ok i see it now, my bad lol. Thanks guys

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