Find the n th partial sum of the arithmetic sequence. $300,257,214,171,128 \ldots , n = 9$
A) 1926
B) 2304
C) -198
D) 958.5
E) 1152

Question

Quizplus · Accepted Answer

The sequence is arithmetic with the first term $a_1 = 300$ and common difference $d = 257 - 300 = -43$. The formula for the n-th partial sum of an arithmetic sequence is $S_n = \frac{n}{2} (2a_1 + (n-1)d)$. Substituting $n = 9$, $a_1 = 300$, and $d = -43$, we get $S_9 = \frac{9}{2} (2 \times 300 + 8 \times -43) = 1152$.

Find the N Th Partial Sum of the Arithmetic Sequence 300,257,214,171,128…,n=9300,257,214,171,128 \ldots , n = 9300,257,214,171,128…,n=9

Find the N Th Partial Sum of the Arithmetic Sequence $300,257,214,171,128 \ldots , n = 9$