Answer:
1) not diverges
2)not diverges
3) diverges
4)not diverges
Step-by-step explanation:
In geometric series, If the |r|<1 then the series is convergent and if |r|>1 then the series is divergent
Where r is the ratio between the consecutive terms of series.
1) 3/5 + 3/10 +3/20 + 3/40 ......
in the above geometric series
r= (3/10) / (3/5)
= 1/2
= 0.5
As |r|= 0.5 < 1, so the series will not diverge
2) -10+4-8/5 + 16/25 -......
in the above geometric series
r= (4) / (-10)
= -2/5
= -0.4
As |r|= 0.4 < 1, so the series will not diverge
3) ∑ 2/3(-4)^(n-1)
in the above geometric series
r= -4
As |r|= |-4| = 4 > 1, so the series will diverge
4) ∑ (-12)(1/5)^(n-1)
in the above geometric series
r=1/5
= 0.2
As |r|= 0.2 < 1, so the series will not diverge !
