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Worked solution

Evaluate a finite sum on the supplied calculator

Evaluate ∑r=28r4(r−1)\sum_{r=2}^{8}r^4(r-1) using the calculator summation command illustrated in the source.

CJC · Sequences and Series · Unnumbered calculator example, page 24

Answer

5300453004.

Compare your reasoning

Select the summation template

On the supplied device, press MATH and scroll to option 0. Alternatively press ALPHA WINDOW and select option 2.

Enter both bounds and the formula

∑X=28X4(X−1)\sum_{X=2}^{8}X^4(X-1)

Use lower bound 2, upper bound 8 and X^4(X−1) as shown. X is the calculator counter corresponding to r.

Evaluate and check

16+162+768+2500+6480+14406+28672=53004\begin{aligned}&16+162+768+2500\\ &{}+6480+14406+28672\\ & =53004\end{aligned}

Press Enter. The screen shows 53004. The explicit seven-term arithmetic is an authored independent check, not another printed calculator instruction.

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