Question

pleasee help im trying to finish a test :D
what are the first three terms of the arithmetic series if a1 = -1, an = -115, and Sn = -1160?

Answer 1

Are you doing your test right now?

Answer 2

yess im timed

Answer 3

half hr left and im stuck on 6 questions

Answer 4

out of 25

Answer 5

are these saposed to be three different series?

Answer 6

We're not supposed to help you cheat in your test.

Here's something you may find it useful.
1. Sn = (a1+an) n /2 <- find n here.
2. an = a1 + (n-1)d <- find d here
3. find the three term you need using the formula in (2).

Answer 7

a.
-1160, -1166, -1172
c.
20, 14, 8
b.
-1, -7, -13
d.
-115, -121, -127

Answer 8

Assume Sn is the sum of AS up to nth term.

Answer 9

its summer school, i just need this credit. and i dont understand what your saying

Answer 10

Are you allowed to get help while you're doing your test?

Answer 11

im at home yeahh im allowed to use whatever i want but i cant find anything online that helps

Answer 12

Still, I'm not sure if it is considered as cheating, especially when it is a *test*

As mentioned above, way to solve this question:
1. Sn = (a1+an) n /2 <- find n here.
2. an = a1 + (n-1)d <- find d here
3. find the three term you need using the formula in (2).

Sub. the values you have, find the values you need.

Answer 13

so i used these Sn = (a1+an) n /2 <- find n here.
an = a1 + (n-1)d <- find d here and i got -60?

Answer 14

idk wth im doing hahah

Answer 15

not possible.

Answer 16

-1160=(-1r-115) right

Answer 17

no.

Answer 18

its cool im just gunna gess i wasted too much time on thsi one question

Answer 19

Sn = (a1+an) n /2
a1 = -1
an = -115
Sn = -1160