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Binomial Expansion: (1 + px + qx²)^-2

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By Anonymous on Friday, January 26, 2001 - 10:35 am:

Hi,

How do you go about expanding the following:

(1 + px + qx²)^-2

Thanks in advance for any help.

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By Kerwin Hui (Kwkh2) on Friday, January 26, 2001 - 01:58 pm:

First, let t=px+qx², then we expand (1+t)^-2=1-2t+3t²-...

Now substitute t=px+qx², and expanding out t² and t³, etc. in terms of x. This should give you what you want.

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By Anonymous on Friday, January 26, 2001 - 03:17 pm:

Thank you Kerwin.

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