Thermodynamics and differentials and Maxima



http://www.math.unm.edu/~wester/demos/Calculus/Macsyma.problems 

contains

(c27) /* Exact differential => d(V(P, T)) => dV/dP DP + dV/dT DT */
diff(V(P, T));
Time= 0 msecs
		  d			  d
(d27) 		 (-- (v(p, t))) del(t) + (-- (v(p, t))) del(p)
		  dt			  dp


I couldn't find any documentation on del(), but as a wild guess I tried:

(C1) U: 'diff(U,S)*S + 'diff(U,V)*V;
			      dU       dU
(D1) 			      -- V + S --
			      dV       dS
(C2) diff(U);
			 dU	     dU
(D2) 			 -- DEL(V) + -- DEL(S)
			 dV	     dS



-----Original Message-----
From: Mike Thomas [mailto:miketh at brisbane]
Sent: Wednesday, 27 March 2002 6:28 
To: Maxima List
Subject: Thermodynamics and differentials and Maxima


Hi all.

How would I express and manipulate in Maxima, equations with exact
differentials as commonly done in thermodynamics eg, go from this equation
to the next


        delta U        delta U
U =  -------  S + ------- V + ...
        delta S        delta V


         delta U         delta U
dU = ------- dS + ------- dV +.....
         delta S          delta V