I was looking at a derivation of entropy expressed as an absolute probability:(adsbygoogle = window.adsbygoogle || []).push({});

S = -k. SUM P.lnP

(What is the name of this by the way?)

In the derivation, it makes the following statements which I really just dont get!

U = SUM E.P

so therefore dU = SUM E.dP - SUM P.dE

Where does the minus sign come from? Should it not be a plus??

Then, it goes from dS = -k. SUM lnP.dP to dS = -k.d(SUM P.lnP)

How is that true?? First it was just P that was a differential element, now its the whole expression in the bracket??

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# Absolute Entropy (Statistical)

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