- #1

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Thank you!

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- Thread starter scientifico
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- #1

- 181

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Thank you!

- #2

- 798

- 34

Simply expand :

(x^0+x^1+x^2+...+x^n)(x-1)

(x^0+x^1+x^2+...+x^n)(x-1)

- #3

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I didn't understand why you wrote (x-1) after the expansion... thank you

- #4

HallsofIvy

Science Advisor

Homework Helper

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If A= B/(x- 1) then A(x- 1)= B.

Is that true here?

x

That is not, however, how I would handle this problem. I would note that [itex]x^0+ x^1+ x^2+ \cdot\cdot\cdot+ x^n[/itex] is a

[tex]\frac{1- x^{n+1}}{1- x}= \frac{x^{n+1}- 1}{x- 1}[/tex].

- #5

- 798

- 34

I didn't understand why you wrote (x-1) after the expansion... thank you

You will understand if you make the multiplication of the series by (x-1) and then simplify. Just do it !

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