kill(all)$

peter.vlasschaert@gmail.com,13/07/2017  'version 1'

REDLICH-KWONG EQUATION OF STATE (thermodynamics part 4)
=>       P=(R*T)/(V-b)-a/(sqrt(T)*V*(b+V))

p1:P=R*T/(V-b)-a/(sqrt(T)*V*(V+b));

p2=(dP/dV) =0  by T = T_c , V = V_c ,  (index : c =critical)

p2:diff(p1,V,1)$
p3:ev(p2,V=V_c,T=T_c);

p5=(d(dp)/dV^2) =0  by T = T_c , V = V_c ,  (index : c =critical)

p5:diff(p1,V,2)$
p6:ev(p5,V=V_c,T=T_c);

find : a,b (from p3,p6)

p8:part(solve(p3,a),1);

find b:

p9:ev(p6,p8);
p10:ratsimp(part(solve(p9,b),1));

find a:

p11:ev(p8,p10);

find  P=P_c

p12:ev(p1,P=P_c,T=T_c,V=V_c);

p13:ev(p12,p11,p10);

find : V_c

p18:part(solve(p13,V_c),1);

find a,b:

find b with V_c

p19:ev(p10,p18);

find a with V_c

p20:ev(p11,p18);