Question

Find S15 for the series -1 + -3 + -5 + -7 +…

Answer 1

do you know the formula of arithmetic sequence

Answer 2

@wizkid701 do you speak english?

Answer 3

yeah

Answer 4

ahh sweet, why you're not talking? :) ... I don't eat humans. If you don't know the formula it's ok, I just want to know if you do.

Answer 5

no i dont but i would like to find out

Answer 6

\[\LARGE a_n=a_1+(n-1)d\]
and difference is
\[\LARGE d=a_{n}-a_{n-1}\]

example:
\[\LARGE d=a_2-a_1\]
can you find "d" ?

Answer 7

wow thanks