Solve Exponentials Problem: ln((V+v)/(V-v)) = 2ctV

  • Thread starter Thread starter Nevermore
  • Start date Start date
AI Thread Summary
The discussion revolves around solving the equation ln((V+v)/(V-v)) = 2ctV for v. The initial approach incorrectly applies logarithmic properties, leading to confusion in the calculations. A correct method involves using the definition of logarithms, where if ln(a) = b, then e^b = a. By applying this definition, the equation can be rewritten as (V+v)/(V-v) = e^(2ctV), which can then be solved for v. The focus is on clarifying the correct application of logarithmic rules to derive the desired expression for v.
Nevermore
Messages
10
Reaction score
0
I have ln((V+v)/(V-v)) = 2ctV, and I've checked this is right. But how do I go from here to v = V((e^Vct - e^-Vct)/(e^Vct+e^-Vct))? The solutions just give them as successive lines.

(I appreciate that's not the easiest thing to read, it's taken from the 2004 MEI specimen paper for A-level Mechanics 4, if that helps.)
 
Mathematics news on Phys.org
HINT: Laws of logs;

\ln\frac{a}{b} = \ln|a| - \ln|b|
 
OK, so
ln((V+v)/(V-v)) = 2ctV
=> ln(V+v)-ln(V-v) = 2ctV
ln(V)ln(v) - ln(V)/ln(v)
2ln(v) = 2ctV
v = e^Vct

Is this right? Where can I go from here?
 
Nevermore said:
OK, so
ln((V+v)/(V-v)) = 2ctV
=> ln(V+v)-ln(V-v) = 2ctV
ln(V)ln(v) - ln(V)/ln(v)
2ln(v) = 2ctV
v = e^Vct

Is this right? Where can I go from here?

there is something wrong in what u have written... first of all
log(a*b) = log(a) + log(b)...what u have used is log(a+b) = log(a) * log(b)..even after that u have written something wrong...check it once more...
anyway u don't need to use that...use the basic definition of logs...
if ln(a) = b
=> e^b = a
 
In other words,
\frac{V+v}{V-v}= e^{2ctV}
Solve that for v.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...

Similar threads

Back
Top