Question

last question ! @RaphaelFilgueiras

Answer 1

Find the sum of the first 8 terms of the sequence. Show all work for full credit.

1, -3, -7, -11, ...

Answer 2

i's the same formula aas before

Answer 3

what is the ratio?

Answer 4

like how much its increasing?

Answer 5

yes

Answer 6

-3

Answer 7

-4

Answer 8

ok

Answer 9

an=a1+(n-1).r

Answer 10

find a8 and the use the prevously formula

Answer 11

a8 would be -27 right?

Answer 12

im confused

Answer 13

i dont get that formula

Answer 14

yes i's -27

Answer 15

Sn=(a1+an).n/2

Answer 16

what is a1? the first term?

Answer 17

yes

Answer 18

so it would be Sn=(1+

Answer 19

what is an? @RaphaelFilgueiras

Answer 20

a1,a1+r,a1+2r,...,a1+(n-3).r,a1+(n-2).r,a1+(n-1).r

see if um sum the last with the first therm the result is the same as the second with penultimate

Answer 21

that were that formula come from, an is the last therm

Answer 22

1,3,5,7,9
1+9=7+3 and 5 =10/2

Answer 23

ahhh im confused

Answer 24

so this is the question
Find the sum of the first 8 terms of the sequence

Answer 25

then we have ((n-1)/2)(a1+an)+(a1+an)/2=(a1+an).n/2

Answer 26

S8=(a1+a8).8/2

Answer 27

so the answer would just be 4? @RaphaelFilgueiras

Answer 28

no, look at the fisrt therms do uou think that sum can be 4?

Answer 29

not at all hahaha

Answer 30

at least it must be a negative number lol

Answer 31

1,-3,-7,-11,-15,-19,-23, -27 @RaphaelFilgueiras

Answer 32

S8=(1-27).8/2=-104

Answer 33

yay!