Sigma Notation
- Thread starter RJ22
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D
Deleted member 4993
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It is not a question of "rather than". It can be either
\(\displaystyle \displaystyle{\sum_{n=5}^{10}nx \ = \ \sum_{n=1}^{6}(4x + nx)} \ = \ 24x \ + \ \sum_{n=1}^{6}nx\)
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Steven G
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- Dec 30, 2014
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I would write the 4x + nx as (4+n)x if you wanted to do it your way.
Here is how I try to figure out how to write something in sigma notation.
1)I look at the terms and see what is exactly the same in each one. In your case the terms are 5x, 6x, 7x, 8x, 9x and 10x. They all have an x.
2) Then I look at what is changing in each term. I note that the x is being multiplied by 5 then 6 then 7...then 10. So n is going from 5 to 10.
Hence
10
E nx
5