Two sums and two variables

[re4m]

How to write an equation in mathcad with two sums and two variables
For example: sum of all i-es and sum of all j-es, of equation q*k*y[sub]ij[/sub]

 

[re4m]

I forgot to tell, program is Mathcad

 

[IRstuff]

It's just a double summation, using the range variable summation <shift>4 twice

TTFN
faq731-376

 

[re4m]

Here is my problem, to simplify it

 

[IRstuff]

I don't understand. You haven't defined anything at all, other than about 5 constants. What is t[i,j? why is k only k, when it appears that you want it dependent on t[i,j?

I suggest that you use the help files and read the examples, or ask your instructor

TTFN
faq731-376

 

[re4m]

QLFG = maximum expected LFG generation flow rate (m3/yr)
i = 1 year time increment
n = (year of the calculation) – (initial year of waste acceptance)
j = 0.1 year time increment
k = methane generation rate (1/yr)
Lo = potential methane generation capacity (m3/Mg)
Mi = mass of solid waste disposed in the ith year (Mg)
t[ij] = age of the j-th section of waste mass Mi disposed in the i-th year (decimal years)
MCF = methane correction factor
F = fire adjustment factor

My job is to solve this equation, but I have to explain mathcad this t[i,j] variable, because it's dependable of i and j. Even if I assign this variable with any number, my equation won't work... Anyone?

 

[IRstuff]

What I meant is that you have failed to enter any VALUES to the variables. How do you expect a program calculate an answer where you've provided no inputs?

TTFN
faq731-376

 

[re4m]

Now I entered values... only I don't know how to define t[i,j]

 

[IRstuff]

Well, don' you think you're going to need a table of 160 values to enter? You can insert an Excel component, which will create an embedded worksheet, through which you can add in the values you need

TTFN
faq731-376

 

[re4m]

I think of that, just occured to me, well, thanx for now, if I need something else... Thanx a lot man