Re-Expressed Equation of Change for Kinetic Energy

The next task is to replace the pressure gradient in equation (25-13) via the total differential of specific enthalpy dh, where h is written in terms of its natural 

The unit vector in the x direction multiplied by the partial derivative of equation (25-14) with respect to x, 

In summary, the total differential of any thermodynamic property can be written in vector notation by replacing differentials with gradient operators. This is convenient because one can rearrange (25-16) to solve for the pressure gradient  

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