Mathetica function (help fix my equation please)

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SUMMARY

The discussion focuses on troubleshooting a Mathematica equation that produces errors during summation. The user encounters issues with iterator localization and raw object usage in the summation function, specifically with the expressions involving n[1] and n[2]. Solutions include correcting the summation syntax to use proper variable localization, such as replacing 'z' with 'i' in the summation. Additionally, the user seeks guidance on formatting absolute values and real numbers in LaTeX for better presentation in physics forums.

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Shawj02
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Hi guys,

I have a problem with Mathematica. The equation (see attachment) is SUPPOSE TO give:
n[0]=n0
n[1]=x0-n0
n[2]=x1-x0+n0
n[3]=x2-x1+x0-n0
n[4]=x3-x2+x1-x0+n0
n[5]=x4-x3+x2-x1+x0-n0
n[6]=x5-x4+x3-x2+x1-x0+n0-1
...

But when I put in n[1] I get the following errors and output:

Sum::itraw: Raw object 1 cannot be used as an iterator. >>
Sum::vloc: The variable 1 cannot be localized so that it can be assigned to numerical values. >>
Sum::itraw: Raw object 1 cannot be used as an iterator. >>
Sum::vloc: The variable 1 cannot be localized so that it can be assigned to numerical values. >>
\sum _{1=1}^1 (-1)^{1-1} x_{1-1}-n_0

What do I need to change to give me an output of x_ 0 + n_ 0n[2] gives:
\sum _{2=1}^2 (-1)^2 x_{2-1}+n_0
when I want it to give me: x_1-x_0-n_0
 

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jedishrfu said:
You might try TexForm to do a conversion to Latex:

http://reference.wolfram.com/language/ref/TeXForm.html

I been playing around with the LATEX thing.. using Mathematica's right click and "copy as Latex" function.
I have attached a copy of my original equation, below is an attempt to convert it into Latex.

\sum _{z=1}^z (-1)^z x_{z-1}-\sum _{z=6}^z 1+n_0 (-1)^z

There seems to be a problem with "Reals" and "Absolutes" How do I do these in Latex?
 

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The problem is your summation.
Shawj02 said:
\sum _{z=1}^z (-1)^z x_{z-1}-\sum _{z=6}^z 1+n_0 (-1)^z
\sum _{z=1}^z f(z) is bad input. It should be something like
\sum _{i=1}^z f(i)
 
Dale said:
The problem is your summation.
\sum _{z=1}^z f(z) is bad input. It should be something like
\sum _{i=1}^z f(i)

Yep, you're right! I've got it working perfectly now!

My other question is: How do I write the ABS and REALS in LATEX? (so I can post things on physics forms better)

so far I've got:

\sum _{j=1}^z (-1)^j x_{j-1}-\sum _{j=6}^z 1+n_0 (-1)^z
 

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Shawj02 said:
My other question is: How do I write the ABS and REALS in LATEX? (so I can post things on physics forms better)
When I am trying to troubleshoot I would rather just have the straight code. The fancy formatting is nice, but makes finding code errors more difficult. I know that isn't everyone's preference, but it is my preference. I would just use the "code" tag and copy and paste the Mathematica input.
 

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