Question

What is the sum of the arithmetic sequence 8, 15, 22 …, if there are 26 terms?
@kc_kennylau

Answer 1

Let \(a\) be the first term, \(d\) be the common difference, and \(n\) be the number of terms.
Sequence: \(a, a+d, a+2d, \cdots, a+(n-1)d\)
Series: \(\dfrac n2[{2a+(n-1)d}]\)

Answer 2

whats the formula for sequence @kc_kennylau

Answer 3

that is the one he has labeled as seris

Answer 4

oohh

Answer 5

oops he copied it twice

Answer 6

?

Answer 7

guess not, I've just not seen it written that way