## Integration

## Integration

(OP)

How do I enter the following into an integration calculator to solve for s?

Sum(n= 0 to infinity, s^2/(n^2-s^2)) when the sum value has a known value (i.e. sum() = 0.40348)

Sum(n= 0 to infinity, s^2/(n^2-s^2)) when the sum value has a known value (i.e. sum() = 0.40348)

Dennis Kirk Engineering

www.ozemail.com.au/~denniskb

## RE: Integration

## RE: Integration

Yes it is a sum and not an integration.

I am trying to use the online Wolfram calculator

Dennis Kirk Engineering

www.ozemail.com.au/~denniskb

## RE: Integration

I tried at Wolfram:

https://www.wolframalpha.com/input/?i=infinite+ser...

It did not seem to have a way to solve for a particular summation.

## RE: Integration

## RE: Integration

Dennis Kirk Engineering

www.ozemail.com.au/~denniskb

## RE: Integration

1/2 (-π s cot(π s) - 1) = 0.48

Rewrite as below and put it back in WA:

(-1 - Pi s Cot[Pi s])/2 - 0.48=0

This will have multiple solutions.

## RE: Integration

Hope this helps

/PB

## RE: Integration

Re-entering the original formula in the form suggested by WA provides several solutions one of which is the one I want (i.e. 0 < s < 1)

Is there a way to limit the range for s within the WA input?

Dennis Kirk Engineering

www.ozemail.com.au/~denniskb

## RE: Integration

## CODE --> WA

## RE: Integration

Doug Jenkins

Interactive Design Services

http://newtonexcelbach.wordpress.com/

## RE: Integration

IDS yes this is also useful though WA provides the same on the second pass

Can anyone suggest a way to solve directly from the original formula in Excel via macro?

i.e. Sum[s^2/(n^2 - s^2), {n, 1, Infinity}]=0.40435 for s>0, s<1

Note that I need to run this calculation multiple times for various values of = 0.40438 and thne again with a slightly different formula and then run this for various values of the function.

i.e. Sum[s/(n^2 - s^2), {n, 1, Infinity}]=0.56037 for s>0, s<1

Dennis Kirk Engineering

www.ozemail.com.au/~denniskb

## RE: Integration

If

Then

TTFN (ta ta for now)

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