# One equation one unknown

## Homework Statement

i want to find the value of k in the following equation:
8.7-(0.75/k)=[e^(8k)](11.7-(0.75/k))

## The Attempt at a Solution

i know i can use matlab but i dont have matlab and i dont even know how to do it on matlab; does anyone know how to do it on matlab?
is there an alternative method to find k?

thank you

Dick
Homework Helper
If you don't have any special tools, write the problem as f(k)=exp(8*k)*(11.7-.75/k)-(8.7-0.75/k). Now you want to find where f(k)=0. Now graph it and look for a zero, or just try different values of k until you find one where f(x) is positive and one where it's negative. E.g. f(0.03)<0 and f(0.04)>0. That means there is a root between 0.03 and 0.04. Try the midpoint k=0.035 and keep refining the interval containing the root until you get enough significant digits for the needs of the problem. This is called 'bisection'.

yes i know that method but it takes too long and i'm lazy.
i just need the answer without the working out so i dont want to take too much time finding the value for k.

cristo
Staff Emeritus
yes i know that method but it takes too long and i'm lazy.
i just need the answer without the working out so i dont want to take too much time finding the value for k.

Well, you should just probably wait until you get to a computer with maple or matlab or whatever. Otherwise, you'll need to do it the long way!

HallsofIvy