The laws of thermodynamics, when placed in a mathematical format are known as Gibb’s fundamental equation. If both the laws are placed in a single format, it comes down to:
dU – TdS + PdV ≤ 0
dU: Variation in internal energy standards
T: Variation in temperature
dS: Entropy variation standards
P: Pressure level
dV: Volume variation
In either case, working body is simple and there is no other force acting on it apart from gravitational force. When theoretical structure is considered, both these laws are taken into consideration apart from zeroth law, which has temperature as an issue and third law that makes use of free energy standards.