The total pressure between two points, ($$a$$ and $$b$$) can be calculated with integration as
$\Delta P_{ab} = \int_a^b \dfrac{dP}{dx} dx \label{phase:eq:TdeltaP} \tag{39}$
$\Delta P_{ab} = \overbrace ParseError: invalid DekiScript (click for details) Callstack: at (Under_Construction/Purgatory/Book:_Fluid_Mechanics_(Bar-Meir)__-_old_copy/13:_Multi–Phase_Flow/13.7:_Homogeneous_Models/13.7.1:_Pressure_Loss_Components/13.7.1.4:_Total_Pressure_Loss), /content/body/p/span[1], line 1, column 1  ^{friction} + \overbrace ParseError: invalid DekiScript (click for details) Callstack: at (Under_Construction/Purgatory/Book:_Fluid_Mechanics_(Bar-Meir)__-_old_copy/13:_Multi–Phase_Flow/13.7:_Homogeneous_Models/13.7.1:_Pressure_Loss_Components/13.7.1.4:_Total_Pressure_Loss), /content/body/p/span[2], line 1, column 1  ^{acceleration} + \overbrace ParseError: invalid DekiScript (click for details) Callstack: at (Under_Construction/Purgatory/Book:_Fluid_Mechanics_(Bar-Meir)__-_old_copy/13:_Multi–Phase_Flow/13.7:_Homogeneous_Models/13.7.1:_Pressure_Loss_Components/13.7.1.4:_Total_Pressure_Loss), /content/body/p/span[3], line 1, column 1  ^{gravity} \label{phase:eq:TdeltaPpart} \tag{40}$