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Telescoping Series

Find $S_r = 1^r + 2^r + 3^r + ... + n^r$ where r is any fixed positive integer in terms of $S_1, S_2, ... S_{r-1}$.

Growing

Which is larger: (a) 1.000001^{1000000} or 2? (b) 100^{300} or 300! (i.e.factorial 300)

Climbing Powers

$2\wedge 3\wedge 4$ could be $(2^3)^4$ or $2^{(3^4)}$. Does it make any difference? For both definitions, which is bigger: $r\wedge r\wedge r\wedge r\dots$ where the powers of $r$ go on for ever, or $(r^r)^r$, where $r$ is $\sqrt{2}$?

Mega Quadratic Equations

Age 16 to 18 Challenge Level:

There are six possible solutions to each of the following equations. Can you find them all?

1. $(n^2 - 5n + 5)^{(n^2 - 11n + 30)} = 1$

2. $(n^2 - 7n + 11)^{(n^2 - 13n + 42)} = 1$

Can you find some more Mega Quadratic Equations like these?



With thanks to Don Steward, whose ideas formed the basis of this problem.
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