1) > bn
2) > 2bn
3) < bn
4) < 2bn
Solution: (2) > 2bn
Consider two numbers an and cn.
[an + cn] / 2 > (an cn)½an + cn > 2 (ac)n/2 —- (i)
Also GM > HM
√ac > b
(ac)n/2 > bn —- (ii)
From (i) and (ii), [an + cn] > 2bn
1) > bn
2) > 2bn
3) < bn
4) < 2bn
Solution: (2) > 2bn
Consider two numbers an and cn.
[an + cn] / 2 > (an cn)½an + cn > 2 (ac)n/2 —- (i)
Also GM > HM
√ac > b
(ac)n/2 > bn —- (ii)
From (i) and (ii), [an + cn] > 2bn