Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

(1/x)+(1.3/xsqr)+(1.3.5/xcube)+.........

Offline

Rajnikanth will always challenge

Bharat mahan hain kiun ki ish desh me Rajnikanth hai

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

Welcome to the forum. I have latexed what I think your question is:

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

i will challenge that i will give 7000 rupees for solving dis problem or any important information about that sequence or range of that sequence

*Last edited by rajinikanth0602 (2012-07-02 02:02:26)*

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

Save the rupees but that sum diverges.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 15,954

Hi bobbym

Is it possible to get a GF of it? I think I have something, but now I am even more unsure of it.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi;

I do not know the answer to that. What I do know is that I have seen that sum before. It is an asymptotic sum. They usually diverge, this one is no different.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

plz bobby sir give any information about it

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

You can call me bobbym here. That is close to my name.

At present, all I know is that it diverges. I do not have anything else. If I get something I will definitely post it for you.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

thank u for ur wonder full replies and i had never saw the sites like this that will take care of every ones problems

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

I guess I should say you are welcome but I have not solved the problem yet.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

watz ur job sir

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi;

Currently I am retired.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

watz ur job sir and say any info about you and frm which country

*Last edited by rajinikanth0602 (2012-07-22 03:37:12)*

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

As I have said, I am retired due to injuries. That means I no longer work.

When I did work my jobs were math related primarily in numerical analysis, combinatorics, probability and programming mainly.

I am from the United States. I am of southern extraction.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**rajinikanth0602****Member**- Registered: 2012-06-30
- Posts: 16

can u give ur email id im frm india

*Last edited by rajinikanth0602 (2012-07-22 03:41:09)*

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

I am sorry but that I can not do on the forum.

Can I ask what you need?

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi rajinikanth0602;

I will do what I can but we can only work through the forum. You can post any problem or most anything right in here. You will receive help and not always from me. There are capable people here.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 15,954

Hi

See if you can use this:

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

Hi;

It is questionable that you will be able to move the y^2 through the Sigma like that. Or maybe you can. What do you get for an answer?

It seems simplest to me to just prove that the numerator of the summand is larger than the denominator. Then you would be adding an infinite number of terms all greater than 1. Terms that are never getting smaller. This looks like it can be done by induction.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 15,954

Hi bobbym

S(sqrt(x)) is the same as the sum above. I just want a closed form. Like 1/(1-x) is the EGF for:

even though the sequence doesn't converge.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

How can you get a closed form? The upper index of summation is not a variable. Either it sums to some constant or it diverges.

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 15,954

Upper index of summation?

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,187

**In mathematics, you don't understand things. You just get used to them.**

**If it ain't broke, fix it until it is.**

Offline

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 15,954

What about it?

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline