Write out the first three terms and the last term of the arithmetic sequence.
-$$\sum _ { i = 1 } ^ { 60 } - 5 i$$
A) $- 1 - 5 - 10 - \ldots - 300$
B) $- 5 - 25 - 125 - \ldots - 1500$
C) $- 5 + 25 - 75 + \ldots - 1500$
D) $- 5 - 10 - 15 - \ldots - 300$

Question

Quizplus · Accepted Answer

The given sequence is an arithmetic sequence with the first term $a_1 = -5$ and common difference $d = -5$. The $n$th term of an arithmetic sequence is given by $a_n = a_1 + (n - 1)d$. For $n = 60$, the last term is $a_{60} = -5 + (60 - 1)(-5) = -5 - 295 = -300$. The first three terms are $-5, -10, -15$, and the last term is $-300$, matching option D.

Write Out the First Three Terms and the Last Term ∑i=160−5i\sum _ { i = 1 } ^ { 60 } - 5 ii=1∑60​−5i

Write Out the First Three Terms and the Last Term $\sum _ { i = 1 } ^ { 60 } - 5 i$