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**woodoo**- Replies: 5

I have a question that says find an unbounded sequence that doesn't diverge to -∞ or ∞. I can't figure one out, I don't think it exists. Anyone know of one?

**woodoo**- Replies: 0

As used in another thread I have this problem

I am asked to find the value of n to approximate the series to the millionth place, then find that approximation. I am confused by this wording. Does anyone understand this and know how I should go about doing this? Thanks

**woodoo**- Replies: 2

I have this problem that I can't figure out.

a_n is a sequence of positive #s. For each n in the natural #s, b_n = (a1+a2+...+an)/n. And I have to use this to show

∞

∑ b_n

n=1

diverges to positive infinity. Any1 have any ideas?

So if Zhylliolom right? Because you guys are confusing me

Oh I understand now, I thought that {bn} was going to have to equal (sin n)/n, I didn't realize you were supposed to break down (sin n)/n into {an} = 1/n and {bn} = sin n to represent

Thank you Zhylliolom

**woodoo**- Replies: 14

I can't grasp the concept of Dirichlet's Test,

I've looked online, but I don't understand it. Can someone give me a simple example to explain it.

Thanks

edit: I think what is confusing me is this:

Am I supposed to prove that is true or do I just assume it is?

**woodoo**- Replies: 1

I have the problem which I must find convergent or divergent:

infinity _____

∑ 1/(√n^3-2)

n= 2

I used the Comparison Test with a p-series to get that it's convergent. Is this correct?

_____ ____

1/(√n^3-2) < 1/(√n^3) = 1/n^(3/2) so it converges

wow that was a lot easier than I thought, thank you

**woodoo**- Replies: 3

The problem I have wants me to prove the following statement false:

"If a_n and b_n are both divergent sequences then (a_n + b_n) diverges also."

I can't come up with a two divergent sequences that with converge if I add them together. Anyone have any ideas? Thanks

Are you sure an isn't (sin(n))/n ?

**woodoo**- Replies: 4

I need to use Dirichlet's test to show

infinity

∑ (sin(n))/n converges

n=1

Would 1/n work for bn? And how shall I go about solving this.

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