- #1
binbagsss
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- 11
Homework Statement
I have a variable ##s_i## with probability distribution ##w(s_i)##
##(\Delta(s_i))^2## denotes the variance ##=<(s-<s>)^2>=<s^2>-<s>^2##
I want to show ## \sum\limits_{i\neq j} <\Delta s_i> < \Delta s_j> =0 ##
where ## < > ## denote expectation
My book has:
## <\Delta s_i> =\int ds_i w(s_i)(s_i-<s_i>)=0##
I don't really understand this so the first term gives ##<s_i>## that's fine which would obviously cancel with a ##<s_i>## but isn't the second term ##E(<s_i>)## not ##<s_i>## so how do they cancel?
Many thanks in advance.
Homework Equations
see above
The Attempt at a Solution
[/B]
I don't really understand this so the first term gives ##<s_i>## that's fine which would obviously cancel with a ##<s_i>## but isn't the second term ##E(<s_i>)## not ##<s_i>## so how do they cancel?
Many thanks in advance.