My Math Forum  

Go Back   My Math Forum > Science Forums > Computer Science

Computer Science Computer Science Forum

Closed Thread
LinkBack Thread Tools Display Modes
August 31st, 2010, 09:49 AM   #1
Joined: Aug 2010

Posts: 3
Thanks: 0

Logarithms and Reversing them

Not sure if this is the right area.... been out of math for awhile.

Log10(P) =( A - (B / T) - (C * Log10(T)) + (D * T) + (( E * (F - T)) / F * T) * Log10(F - T))

Formula for r22 temperature to pressure conversion
Where if T = 50 then P = 85 (rounded)

Now I am trying to reverse it to Get T from P, according to Antoine Equation for pressure temperature relations T = (B / (A - Log10(P))) - C

But I can't figure out the rest of the reverse equation to get the Temperature from the Pressure

A = 29.35754453
B = 3845.1931152
C = 7.86103122
D = 0.002190939044
E = 305.8268131
F = 686.1

This are the Fixed Coefficients for the Whole Calculations if anyone needs them...

Liqwde is offline  
August 31st, 2010, 12:24 PM   #2
Global Moderator
CRGreathouse's Avatar
Joined: Nov 2006
From: UTC -5

Posts: 16,046
Thanks: 938

Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms
Re: Logarithms and Reversing them

There isn't going to be any nice inverse formula. I'm not even sure if you could solve it explicitly with Lambert's W. The best way would be with a numerical method like the secant method or Brent's method.
CRGreathouse is offline  
August 31st, 2010, 09:59 PM   #3
Global Moderator
Joined: Dec 2006

Posts: 20,096
Thanks: 1905

Problem already posted and replied to here: viewtopic.php?f=13&t=15557
so topic locked.
skipjack is online now  
Closed Thread

  My Math Forum > Science Forums > Computer Science

logarithms, reversing

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Help reversing an algorithm... Vidofner Applied Math 4 January 12th, 2014 09:47 AM
Help reversing formula oneup Elementary Math 4 September 2nd, 2013 05:08 AM
Reversing the order of Integration OSearcy4 Calculus 4 October 17th, 2009 04:32 PM
Reversing the order of integration Gotovina7 Calculus 1 February 29th, 2008 10:30 AM
Reversing Digits Cat Number Theory 6 January 7th, 2007 08:32 PM

Copyright © 2019 My Math Forum. All rights reserved.