Student Doctor Network Forums > Pre-Medical Forums > MCAT Discussions > MCAT Study Question Q&A > Logarithm question... PDA View Full Version : Logarithm question... tncekm03-06-2008, 08:35 PMOkay, so I'm trying to derive the Hendersen Hasselbach equation, and its been a LONG time since I've worked with logarithms, so I want to make sure I'm doing this right. I couldn't find an explicit agreement with this via google, so maybe someone here can verify that I've been doing this right (it gives me the right derivation) Log(A/B) = -Log(B/A) b/c Log(A/B) = LogA - LogB --> -Log(A/B) = LogB - LogA --> -Log(A/B) = Log(B/A) --> Log(A/B) = -Log(B/A), correct? Thx EDIT: Just realized I constructed the equation wrong, so I didn't even need this to get HH eqn. But, I'm still interested in whether or not this is a valid proof :D Chemist015703-06-2008, 09:02 PMYep. Basically, LOG(1/X) = -LOG(X) fileserver03-06-2008, 09:29 PMyes, that is correct. or you can do this: " Log(A/B) = -Log(B/A) b/c " = - log (b/a) = - log (b^1 a^-1) = log (b^1 a^-1)^-1 = log (b^-1 a^1) = log (a/b) iA-MD201303-06-2008, 10:16 PMlooks good :) tncekm03-06-2008, 10:16 PMAwesome, thx everyone. werd03-07-2008, 05:56 PMit's always bugged me that hendersen/hasslebach got this 'famous' equation named after them... all they did was rearrange the equillibrium equation. it wasn't even a complex rearrangement; it can be empirically derived in about 45 seconds using algebra. oh well. tncekm03-08-2008, 12:35 AMit's always bugged me that hendersen/hasslebach got this 'famous' equation named after them... all they did was rearrange the equillibrium equation. it wasn't even a complex rearrangement; it can be empirically derived in about 45 seconds using algebra. oh well. Yeah... I agree. If you want to talk about WEAK how about the rest mass energy equation: E=mc² Its only three letters! :D