SOLUTION: Find the Sn of the given artithmetic series. a1=-100, d=-1, n=21

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Question 1043122: Find the Sn of the given artithmetic series.
a1=-100, d=-1, n=21
Answer by ikleyn(52790) About Me  (Show Source):
You can put this solution on YOUR website!
.
Find the Sn of the given highlight%28cross%28artithmetic%29%29 arithmetic series.
a1 = -100, d = -1, n = 21
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S%5Bn%5D = %28a%5B1%5D+%2B+%28n-1%29%2Ad%2F2%29%2An = %28-100+%2B+%2821-1%29%2A%28-1%29%2F2%29%2A21 = .?.


.?. means "calculate on your own".

On arithmetic progressions read the lesson
    - Arithmetic progressions
in this site and the lessons associated with it.