+0  
 
0
252
3
avatar+50 

This: ∑iXij2

 Apr 28, 2018

Best Answer 

 #2
avatar+27396 
+5

I suspect this means something like:

 

X is a matrix with, say, N rows and M columns.  Subscript i runs from 1 to N; subscript j runs from 1 to M.

 

\(\Sigma_iX_{ij}^2\) returns the sum of the squares of all elements from row 1 to row N in column j.

 Apr 28, 2018
edited by Alan  Apr 28, 2018
 #1
avatar+95375 
+2

Well that is a part of a bigger question but it looks like it could a part of a matrix question.

It doesn't make sense on its own.

 Apr 28, 2018
 #2
avatar+27396 
+5
Best Answer

I suspect this means something like:

 

X is a matrix with, say, N rows and M columns.  Subscript i runs from 1 to N; subscript j runs from 1 to M.

 

\(\Sigma_iX_{ij}^2\) returns the sum of the squares of all elements from row 1 to row N in column j.

Alan Apr 28, 2018
edited by Alan  Apr 28, 2018
 #3
avatar+50 
0

Thanks! :)

 May 1, 2018

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