Question

s=1-1/3+1/9-...

Answer 1

use formula :
s= a/(1-r)
with a=first term
r=ratio=u2/u1=u3/u2

Answer 2

huh?

Answer 3

its a geometric progression with contant ratio(r)=-1/3
and its first term(a) is 1
hence we can use a formula for the sum of this g.p. as a(1-r)

Answer 4

ok, a=1 and r=(-1/3)/1 = -1/3
plug in a=1 and r=-1/3 to that formula!

Answer 5

soooo its 3/4??

Answer 6

yup

Answer 7

sorry i did a mistake in the formula it will be a/(1-r)

Answer 8

do u do it the same way when the question is 4/3+2/3+1/3...

Answer 9

yea, that's right.

Answer 10

yes here the ratio(r) is 1/2 ..

Answer 11

k thx

Answer 12

oke, what's answer do u get ?