How to determine exact differentials

[relativespeak]

Homework Statement

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Homework Equations

The Attempt at a Solution

I'm not having trouble with the first part, just having trouble understanding why dQ is not exact but dS=dQ/T is. At first I was thinking that it had to do with the V in the dT part of the dQ equation because the single V does not account for changes in V, but this part still exists in the entropy equation. Please help me conceptualize what it means to be an exact differential.

 

[tiny-tim]

hi relativespeak!

… having trouble understanding why dQ is not exact but dS=dQ/T is.

the book is a little misleading

it means that, as a function of V and T, dQ is not an exact differential, but dQ/T is

of course, if we ignore V ant T, dQ is an exact differential … of Q !

 

[voko]

What is the differential of a two-variable function?