Question

Find Sn, for the given arithmetic series.

a = –26, d = –9, n = 24

Answer 1

first find \( a_{24}\)
\[\Large a_{24}=a_{1}+23d=-26+(23)(-9)=-233\]
now use
\[\Large S_{n}=\frac{n}{2}[a_{1}+a_{n}]\]
where
a1=-26
an=-233
n=24
just plug in the values in the formula given below
\[\Large S_{n}=\frac{n}{2}[a_{1}+a_{n}]\]

Answer 2

ohhhkay thanks i wasn't dividing n by two, but i did everything else. thanks bro!

Answer 3

you are welcome :)