got stuck in equation

Chris Angelico rosuav at gmail.com
Tue Jan 1 18:44:46 CET 2013


On Wed, Jan 2, 2013 at 3:42 AM, Dave Angel <d at davea.name> wrote:
> On 01/01/2013 11:03 AM, Chris Angelico wrote:
>> This isn't a Python question, it's an algebra one. I don't know what
>> Z, S, and so on are, but for the most part, the basic rule of solving
>> equations applies: Do the same thing to both sides and it's still
>> true. Work on it until you can isolate SN on one side.
>
> Such a rule may not be able to solve an equation when there SN appears
> more than once on the RHS, and where it's inside a transcental
> function.  I don't consider this an algebra problem, but a programming
> problem.

It's a tad more complicated than your average equation, and I haven't
the time now to prove the point by actually solving it, but every
operation that I can see in that formula can be reversed. The hairy
bit is that there are two references to SN, so it's going to be a bit
messy to untangle, and might end up as a higher-order equation.

But you're likely right that other forms of solver may be more useful
here. Algebra definitely _could_ be the solution, but it isn't
necessarily the best.

ChrisA



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