# solvable?

• November 4th 2009, 09:05 PM
Etbauer
solvable?
I'm trying to work out a problem, and it comes down to the form A*e^(b*t)+C*e^(f*t) = g. Where everything is constant but t, and I am trying to solve for t. How would one go about this?
• November 4th 2009, 09:20 PM
Bacterius
Is $e$ the neperian logarithm ( $ln$) base ?
And when you say constant, you mean known ? Otherwise you could just sieve, if you always have the same values except $t$ ...
• November 4th 2009, 10:11 PM
Etbauer
yes, e is ln based. And by constant I simply mean not functions of anything else.

So, I am looking to solve for t in terms of the other variables.

This function is a result of setting two equations equal to each otehr so I am trying to solve at what time t they become equal for different parameters.
• November 4th 2009, 10:34 PM
Bacterius
It may be useful to back up and look what A means for C, for instance. You might be able to find common factors, or even better, you may be able to substitute ... So can you post the integrality of the calculations you made ? There might be something you didn't see that makes the solving obvious.
• November 4th 2009, 11:44 PM
CaptainBlack
Quote:

Originally Posted by Etbauer
I'm trying to work out a problem, and it comes down to the form A*e^(b*t)+C*e^(f*t) = g. Where everything is constant but t, and I am trying to solve for t. How would one go about this?

Are there any conections between the constants? What is the context of this problem?

You might find it advantageous to post the original question.

CB
• November 5th 2009, 04:12 PM
Etbauer
ok, here is whre i got that form from, but realize that it does not belong in this forum. As I say in the paper, even if there is another way to go about it, i am curious to know if equations of that form can be solved.
• November 5th 2009, 05:56 PM
Bacterius
Quote:

Originally Posted by Etbauer
ok, here is whre i got that form from, but realize that it does not belong in this forum. As I say in the paper, even if there is another way to go about it, i am curious to know if equations of that form can be solved.

Ouch this is too complex for me :(
• November 5th 2009, 07:54 PM
CaptainBlack
Quote:

Originally Posted by Etbauer
ok, here is whre i got that form from, but realize that it does not belong in this forum. As I say in the paper, even if there is another way to go about it, i am curious to know if equations of that form can be solved.

These problems are generally solved numerically.

CB