What is the sum of the arithmetic sequence 8, 15, 22 …, if there are 26 terms?
1 Answer
Sep 27, 2016
Explanation:
To calculate the
#color(blue)"sum of n terms"# for an arithmetic sequence.
#color(orange)"Reminder " color(red)(bar(ul(|color(white)(a/a)color(black)(S_n=n/2[2a+(n-1)d])color(white)(a/a)|)))#
where a represents the first term and d, the common difference.here a = 8, d = 22 - 15 = 15 - 8 = 7 and n = 26
#rArrS_(26)=26/2[(2xx8)+(25xx7)]#
#=13(16+175)=2483#
