6715sum1.bmp (545 KB)
Why i got different results? Is there a bug with the sum? Or why i got this empty Textcell with a Square?
Any chance you could attach a notebook (.nb) file with the code, or copy-and-paste it into
a code area? (See http://community.wolfram.com/groups/-/m/t/151347 for including code.)
The symptoms suggest that in your expression for w there is an invisible character in it. That would account for your mysterious power of 2 in the second term of Out[44].
One way you might find if this is the case is to execute
FullForm[w[1]]
though I am not sure if it would show… but if you post the notebook intself as Bruce suggests it should be easy to see if this is the case
An unrelated suggestion: never use the letter l (ell) as a variable on its own. It is almost (and for some fonts completely) indistinguisable from the number 1 (one).
Thank you, for the answer.
With
FullForm[w[1]]
Out[44]:= Times[-1,Cos[Subscript[\[Phi],1][t]]\[IndentingNewLine],Subscript[l,1],TextCell[""]]
i found an invisible Textcell. I deleted it. Now it works.
I dont know where it comes from, but it drived me crazy.
Great!
Glad it got figured out.
--Sherlock Holmes