Question

please! check my answer.
Find the sume of series.
2+4+8.....+ 128

Answer 1

4/2= 2 , r=2
126/2 = 63 term
Sn = (1/2) ( 2+ 128)
Sn= 4.095 ?
My anwser not match with key is: 254

Answer 2

no

Answer 3

u can't do 126/2

Answer 4

ur answer wrong

Answer 5

the formula u used is wrong

Answer 6

iit is n/2(a+an)

Answer 7

rate gud answer plzzz

Answer 8

yes that the fomula I use it

Answer 9

(63/2)*(2+126) = 4.095

Answer 10

an=a1*r^(n-1)
128=2*2(n-1)
64=2^(n-1)
2^6=2^(n-1)
6=n-1
n=7

so Sn=a1*(r^n -1)/(r-1)=2*(2^7 -1)/(2-1)=2*127=254

Answer 11

this is the way how u should solve it and is the right one

Answer 12

answer is 254

Answer 13

i got it