I've got a very tricky series question on hand,(adsbygoogle = window.adsbygoogle || []).push({});

I'm given [tex] \sum_{r=1}^{\infty} r^2 = \frac{1}{6} n(n+1)(2n+1) [/tex] and i'm asked to find [tex] \sum_{r=n+1}^{2n} 4r^2 [/tex].

The change of limits and all is killing me ! any ideas on how to start? Thanks.

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# Series Question

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