--> (∂ P∂ T)V = RV
--> (∂ V∂ T)p = RP
--> (∂ V∂ P)T = -RTP2
now use V = RTP in first tem and multiply the three terms
--> (∂ P∂ T)V = RV
--> (∂ V∂ T)p = RP
--> (∂ V∂ P)T = -RTP2
now use V = RTP in first tem and multiply the three terms