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BustedBreaks
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Analysis Questions--Thanks for helping me!
I have a final in an introductory analysis class that covers mostly sequences and series on Friday and I'm a bit behind in the course work. I have a bunch of questions so instead of making a different thread for each one I figured I would just use this one. All the posts with questions will be in bold to distinguish from responses. Thanks in advance for all your help and here's the first question:
Let S be the sequence [itex]<x_{n}>_{n} [/itex] where:A.[tex]x_{n}=1+\frac{(-1)^{n}}{(n+1)}}[/tex], for n=0,3,6,9,...
B.[tex]x_{n}=-1+\frac{1}{n}}[/tex], for n=1,4,7,10,...
C.[tex]x_{n}=\frac{1}{2}+\frac{3}{n}[/tex], for n=2,5,8,11,...
Determine
1. The limsup of S.
2. The liminf of S.
3. Whether S has a limit. The limit as n goes to infinity for A is 1
The limit as n goes to infinity for B is -1
The limit as n goes to infinity for C is 1/2
So there is no limit, to answer 3, because the limits for each subsequence do not equal each other, correct?
I'm not sure what to do about liminf and limsup...
I want to say that the liminf is -1 and the lim sup is 1, but I'm not sure if my reasoning is correct. I just took the least and greatest of the limits as it approaches infinity. Another answer could be that the lim inf is 0 because that is the smallest first number of the sequence, but I don't think that's right because by that logic you can find smaller numbers by using n greater than 0 etc which is why I think taking the infinite limit is the right answer.
I have a final in an introductory analysis class that covers mostly sequences and series on Friday and I'm a bit behind in the course work. I have a bunch of questions so instead of making a different thread for each one I figured I would just use this one. All the posts with questions will be in bold to distinguish from responses. Thanks in advance for all your help and here's the first question:
Let S be the sequence [itex]<x_{n}>_{n} [/itex] where:A.[tex]x_{n}=1+\frac{(-1)^{n}}{(n+1)}}[/tex], for n=0,3,6,9,...
B.[tex]x_{n}=-1+\frac{1}{n}}[/tex], for n=1,4,7,10,...
C.[tex]x_{n}=\frac{1}{2}+\frac{3}{n}[/tex], for n=2,5,8,11,...
Determine
1. The limsup of S.
2. The liminf of S.
3. Whether S has a limit. The limit as n goes to infinity for A is 1
The limit as n goes to infinity for B is -1
The limit as n goes to infinity for C is 1/2
So there is no limit, to answer 3, because the limits for each subsequence do not equal each other, correct?
I'm not sure what to do about liminf and limsup...
I want to say that the liminf is -1 and the lim sup is 1, but I'm not sure if my reasoning is correct. I just took the least and greatest of the limits as it approaches infinity. Another answer could be that the lim inf is 0 because that is the smallest first number of the sequence, but I don't think that's right because by that logic you can find smaller numbers by using n greater than 0 etc which is why I think taking the infinite limit is the right answer.
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