# How to solve equation with many exp

• January 29th 2011, 11:17 AM
Jesy
How to solve equation with many exp
Hi

I'm trying to understand how to solve this type of equation and don't know.
A*exp(x/B)+Cexp(x/D)+Fexp(x/G)+Kexp(x/L)+Mexp(x/N)=0

I need to find x.

Thanks for your help,
• January 29th 2011, 11:55 AM
emakarov
Welcome to the forum.

If one of B, D, G, L, N is a multiple of the rest, then this problem reduces to finding roots of a polynomial. For example, suppose that B = d * D = g * G = l * L = n * N for some positive integer d, g, l, n. Then $e^{x/D}=e^{(x/B)\cdot d}=(e^{x/B})^d$. So, the equation becomes $Ay+Cy^d+Fy^g+Ky^l+My^n=0$ for $y=e^{x/B}$.

Do you need to solve this equation symbolically or numerically? Is there some background knowledge that you need to use? Also, depending on these answers, you need to post this question to the right forum (this one is about discrete mathematics).
• January 29th 2011, 12:06 PM
Jesy
Thank you, that is what I needed. I'll try to work it out