## Solving for a variable with varying parameters in the sum

### NN (view profile)

on 21 Mar 2019
Latest activity Commented on by NN

on 22 Mar 2019

### Walter Roberson (view profile)

being the unknown variable, how to initialize and write the following equation in matlab script containing varying paramters.
(n = 0,1,2,...)

Kevin Phung

### Kevin Phung (view profile)

on 21 Mar 2019
What have you tried?
NN

### NN (view profile)

on 22 Mar 2019
@Kevin
Tried implementing using symbolic variables. It gets complicated and confusing considering the summation and varying m as well as n values.

R2017b

### Walter Roberson (view profile)

on 21 Mar 2019

You cannot. That describes an infinite summation where you need to solve all infinite I_m values.
You cannot truncate it because truncation would imply that if you were to make some I_m indefinitely big for some "large" m, that it would not make a substantial difference to the summation -- but clearly if you know the a_m c_m_n R_m_n values then you can create a corresponding I_m value that overwhelms any previous sum you might have had.

Torsten

### Torsten (view profile)

on 22 Mar 2019
@Walter:
You also have an infinite number of equations - one for each n.
Such problems usually arise if one wants to determine the coefficients of the power series of the product or the quotient of two functions from which the power series are known.
NN

### NN (view profile)

on 22 Mar 2019
@Walter:
What about if instead of a finite number was used, like so:
(n = 0,1,2,...)
As or your second comment, , and have known relations but contain varying parameters too. For example \alpha_m from the above equation = , where π and a are known constants.
Torsten

### Torsten (view profile)

on 22 Mar 2019
How do you intend to exclude the trivial solution I_m = 0 for all m ?