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Topic: Algebraic Manipulation...Equation Inverse
Replies: 0

 Chris Posts: 4 From: AL Registered: 9/9/10
Algebraic Manipulation...Equation Inverse
Posted: Sep 9, 2010 1:47 PM

Dupont Equation for Vapor Pressure Relationship
Log10(P) = A - (B / [C + T]) + D * T + [ E ( F - T ) / FT ] * Log10 ( F - T )

I have programmed this equation into Visual Basic, You enter the Temperature and it calculates the Pressure.

What I need to do is get an Inverse so I can enter the Temperature and get the Pressure

The Dupont is similar to Antoine, maybe a simplified or rewritten form.

Antoine's Equation Log10(P) = A - (B / [C + T])
Antoine's Inverse T = ( B / [A - Log10(P)]) - C

Antoine's Extended Log10(P) = A - (B / [C + T]) + D * T^2 + F * Ln(T)
T^2 = T Power of 2

Because of the Similarity I thought the Antoine Inverse would be a good start.

I've had the suggestions of Lambert's W, The Secant method or Brent's method.

Major problem being my absence and lack of Serious Math experience. (High School Algebra, Algebra 2, Adv Math, Pre Calc.... 11 yrs ago lol)
I Understand the premise, just not something I can do anymore. So, Thought I would run it past people more current and up on theirs skills...

Maybe someone can help me solve this or point me in a direction