Find the first and third partial sums, s1 and s3, for the sequence
-$$a _ { n } = 3 n + 9$$
A)12, 45
B)12, 18
C)12, 36
D)12, 42

Name: Find the first and third partial sums, s1 and s3, for the sequence -\[a _ { n } = 3 n + 9\] A)12, 45 B)12, 18 C)12, 36 D)12, 42
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Question

Quizplus · Accepted Answer

The first partial sum $s_1$ is simply the first term of the sequence, which is $a_1 = 3(1) + 9 = 12$. The third partial sum $s_3$ is the sum of the first three terms: $a_1 + a_2 + a_3 = (3(1) + 9) + (3(2) + 9) + (3(3) + 9) = 12 + 15 + 18 = 45$.

Find the First and Third Partial Sums, S1 and S3 an=3n+9a _ { n } = 3 n + 9an​=3n+9

Find the First and Third Partial Sums, S1 and S3 $a _ { n } = 3 n + 9$