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Find the sum of the first 9 terms of the following sequence. Round to the nearest

hundredth if necessary.
4,
8,
16, ...

1 Answer

7 votes

Final answer:

The sum of the first 9 terms of the sequence is 162.

Step-by-step explanation:

The sum of the first 9 terms of the given sequence can be found by adding each term together.

The sequence is 4, 8, 16, ...

To find the sum, we can use the formula for the sum of an arithmetic series: Sn = (n/2)(a + l), where Sn is the sum, n is the number of terms, a is the first term, and l is the last term.

In this case, the first term is 4 and the ninth term can be found using the formula l = a + (n-1)d, where d is the common difference. The common difference in this sequence is 8 - 4 = 4.

Plugging in the values, we get:

Sn = (9/2)(4 + (4(9)-4)), which simplifies to Sn = (9/2)(4 + 32), and further simplifies to Sn = (9/2)(36) = 162.

So, the sum of the first 9 terms of the sequence is 162.

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