Question

Please Someone HELP! im exhausted its 12 my time!! Please help! Have some sympathy!

Answer 1

14. What is S5 for 1000 + 500 + 250 + ... ?

Answer 2

did you realize that this is geometric sequence with common ratio =... ?

Answer 3

no i didn't

Answer 4

so r=.5

Answer 5

yes, now do you know the general formula of n'th term of geometric series ?

Answer 6

1000+500+250+125+62.5

Answer 7

no i dont

Answer 8

the formula for sum is
\(S_n = a_1\dfrac{r^{n}-1}{r-1}\)
since you need 5 terms sum, n = 5
you already know r = 0.5 and a1 = 1st term = 1000
just plug in values!

Answer 9

i got -3000 thats not an option though

Answer 10

lets check,
1000 (-0.5^5+1)/0.5 = 2000 * 0.96875 = 1937.5 ? is that an option?

Answer 11

yeah it is!! can u help with 2 more please!

Answer 12

yeah, but u need to try them first on your own....you can surely ask for formulas...

Answer 13

the attachment is the question

Answer 14

the series is
2,1,1/2,1/4....
total 16 terms, n=16
a1 = 1st term = 2, r=... ?
then use the same formula.

Answer 15

there is none right?

Answer 16

there is no common ratio

Answer 17

isn't it 1/2 or 0.5 ?

Answer 18

oh oh oops!

Answer 19

I got -0.00012207

Answer 20

and it rounds to 0

Answer 21

is that correct

Answer 22

@hartnn

Answer 23

wait, let me calculate.

Answer 24

i am getting approximately 4...

Answer 25

how u got 0 ?

Answer 26

i dont know! Im so tired I can barley think..... I need to turn this in tommorrow morning!

Answer 27

try, sum as 4.

Answer 28

ok...
11. What is the sum of the finite arithmetic series?

(–5) + 0 + 5 + 10 + ... + 65

Answer 29

here are the choices
900
455
450
445

Answer 30

whats the common difference ?

Answer 31

D=5

Answer 32

yes, formula is S = (n/2) [1st term + last term]
S =... ?

Answer 33

1,950

Answer 34

s=65/2{-5+65}

Answer 35

n= 15
15/2 * (60) = 15*30 =.... ?

Answer 36

450

Answer 37

im not typing... have no idea why its doing that

Answer 38

last one I promise

Answer 39

please @hartnn promise its the last

Answer 40

just a sec, i am solving....

Answer 41

the series is
-1,2,5,8....
so common difference d=.... ?

Answer 42

d=3

Answer 43

yes, a1 = 1st term = -1, n =18
formula is :
\(\S_n = (n/2)[2a+(n-1)d]\)
just plug in values!

Answer 44

441!

Answer 45

yes :)

Answer 46

thanks sooo much now I may sleep! :) thank you thank you thank you!

Answer 47

your welcome ^_^
have sweet dreams :)

Answer 48

thanx :)