Hello,

 I need your help to calculate (approximate) a double series as shown in the attached.

 Thank you so much.

Best,

Steve.double_series.pdf

Without any information about f(i), it can't be done.

Hello mathematic,

    The function f(i) = |2*i - A|, A is a constant.

Best,

Steve. 

double_series.pdf

In the denominator does 2^k multiply j or j+i?

Edited February 1, 20196 yr by mathematic
structure

[(2^k multiply j) + i] in the denominator.

On 2/2/2019 at 10:13 PM, mathematic said:

 

 

[math]\sum_{i=1}^n\sum{j=1}^n\frac{|2i-A|}{2^kj+i}=\sum_{i=1}^n\frac{|2i-A|}{2^k}\sum{j=1}^n\frac{1}{j+2^{-k}i}\approx \sum_{i=1}^n\frac{|2i-A|}{2^k}(ln{n+2^{-k}i})-ln(2^{-k}i))[/math]. 

 

See if you can start here.  I am trying to use Latex - not working.

 

 

Edited July 7, 20196 yr by Strange
latex problem

Hello everyone,

  Is there any update for this problem?

Best regards,

I can't get at my last post to try to fix it.  Essentially I tried to rearrange things so that the j summation could be carried out.

  Try this website.  You are more likely to get a response.  Advise - they have a lot of nitpickers, so define the question as clearly as possible and avoid linking to somewhere else if you can.

 

https://math.stackexchange.com

Edited February 8, 20196 yr by mathematic
remove underline

Thank you so much. If you have any update, let me know. I'm very appreciated to get your help.

First I was wondering by what calculate means, but eitherway i dont think there is a closed form.

On 2/7/2019 at 10:10 PM, mathematic said:

I can't get at my last post to try to fix it.  Essentially I tried to rearrange things so that the j summation could be carried out.

I think I fixed your Latex (no idea if it is correct or not!)