熱力学
dS=CvdT/T+RdV/V
=3RdT/T+RdV/V
dS=0 のとき
0=3R*∂T/T+R*∂V/V
(∂T/∂V)S=-1/3*T/V
TdS=3R*dT+pdV
=4R*dT-Vdp
一方
TdS=3R*dT+pdV
=3(pdV+Vdp)+pdV
=4*pdV+3*Vdp
dV=0 のとき
T∂S=3V∂p
(∂p/∂S)V=1/3*T/V
(∂p/∂S)T=-(∂T/∂V)S=1/3*T/V=p/(3R)