Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
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Exercise 12 Page 825

Start by finding the formula, then use it to find the next two terms.

Next Two Terms: - 216 and - 343
Formula: a_n=- n^3
Explicit or Recursive? Explicit

Practice makes perfect
We want to find a formula for the given sequence. - 1, - 8 - 27, - 64, - 125, ...

Notice that all of the terms in the sequence are cube numbers. We will use this to find the formula.

a_1 a_2 a_3 a_4 a_5 ... a_n
- 1 - 8 - 27 - 64 - 125 ... —
- 1^3 - 2^3 - 3^3 - 4^3 - 5^3 ... - n^3

Since the formula describes the n^(th) term using the number n, it is an explicit formula. Let's use it to find the next two terms.

a_n=- n^3
a_6=- 6^3 a_7=- 7^3
a_6=- 216 a_7=- 343

The next two terms in the sequence are - 216 and - 343.