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What are the next two terms in the sequence 1, 8, 27, 64..., written as coordinate pairs (n,

an)?
A) (5, 75), (6,86)
B) (5, 81), (6,100)
C)(5, 125), (6, 216)
D) (125, 5), (216, 6)

User Endran
by
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1 Answer

1 vote

Answer:

C)(5, 125), (6, 216)

Explanation:

Well firstly, there's no actual way to know. There could be anything there, as for any n pairs (x, y) with distinct x-s, there exists a (n-1 or less)-degree polynomial that models them perfectly, and infinitely many polynomials of degree n (or more).

If we input those terms to a polynomial interpolator, we'll get an answer every time.

With this one, it will be the right answer though!

But to be serious, let's find out what the numbers are. We can notice they're all cubic numbers.

There's 1, which is 1^3, then theres 2^3, then it's 3^3, then 4^3.

It's reasonable to expect that we are expected to assume (x, x^3) is the rule.

We can see that the answer C (5, 5^3), (6, 6^3) fits this narrative.

User Kylaaa
by
5.1k points