Question

Which of the following does not make sense for the series : 2+4+8+16+32+64+128

Answer 1

\[\sum_{n=1}^{7} 2^2 or \sum_{n=0}^{6} 2^n+1 or \sum_{n=2}^{8} 128 (1/2)^ {n-2} OR \sum_{n=1}^{7} 128 (1/2)^{n} \]

Answer 2

(( actually on the first series it has to be 2^n not 2^2)

Answer 3

you figured that out correctly ! you still stuck wid something here ?

Answer 4

Wait no I didn't, I just did a type!

Answer 5

*typo!

Answer 6

for second option, that +1 is at the exponent, right ?

Answer 7

yes!

Answer 8

good :) then except first option, all others are making sense to me. what about u ?

Answer 9

But one of them is incorrect??

Answer 10

first one doesn't make sense

Answer 11

It is supposed to be 2^n because I did a typo

Answer 12

oh i see ok

Answer 13

yea

Answer 14

254

Answer 15

\(\sum_{n=1}^{7} 2^n \ or\ \sum_{n=0}^{6} 2^n+1 \ or\ \sum_{n=2}^{8} 128 (1/2)^ {n-2} \ OR \ \sum_{n=1}^{7} 128 (1/2)^{n} \)

Answer 16

the secone one is actually ^n+1

Answer 17

\(\sum_{n=1}^{7} 2^n \ or\ \sum_{n=0}^{6} 2^{n+1} \ or\ \sum_{n=2}^{8} 128 (1/2)^ {n-2} \ OR \ \sum_{n=1}^{7} 128 (1/2)^{n} \)

Answer 18

Yes!

Answer 19

First option works

Answer 20

second option works

Answer 21

third option works

Answer 22

oh but the 4th doesn't

Answer 23

but doesn't the 3rd not work aswell

Answer 24

fourth option if u expand, lets see what we get :-

\( \sum_{n=1}^{7} 128 (1/2)^{n} \)

\( 128 (1/2)^{1} + 128 (1/2)^{2} + 128 (1/2)^{3} + 128 (1/2)^{4} + 128 (1/2)^{5} + 128 (1/2)^{6} + 128 (1/2)^{7} \)

\( 64+ 32 + 16 + 8 + 4 + 2 + 1 \)

Answer 25

Oh h I see

Answer 26

so fourth option wont work.

Answer 27

lets expand third option and see

Answer 28

\(\sum_{n=2}^{8} 128 (1/2)^ {n-2} \)

\( 128 (1/2)^{2-2} + 128 (1/2)^{3-2} + 128 (1/2)^{4-2} + 128 (1/2)^{5-2} + 128 (1/2)^{6-2} + 128 (1/2)^{7-2} + 128 (1/2)^{8-2} \)

\( 128 (1/2)^{0} + 128 (1/2)^{1} + 128 (1/2)^{2} + 128 (1/2)^{3} + 128 (1/2)^{4} + 128 (1/2)^{5} + 128 (1/2)^{6} \)

\( 128 + 64 + 32 + 16 + 8 + 4 + 2 \)

Answer 29

mhm so that would work ... ?

Answer 30

yep ! only fourth doesnt work, rest everything works

Answer 31

But how come it still works but it is just flipped ?

Answer 32

Also wheny ou plug in "n" for #3 it seems to not make sense ?

Answer 33

128 + 64 + 32 + 16 + 8 + 4 + 2

is same as

2 + 4 + 8 + 16 + 32 + 64 + 128

Answer 34

ohh

Answer 35

I did not know that lol

Answer 36

lol

Answer 37

thnx!