Thread: solve equation for x with lnx and x

Hi, is it possible to solve the equation

y = alnx + bx + c?

I made it myself as it seems to best model something, and want a computer program i'm writing to be able to calculate x. Is this actually possible?

Thanks very much in advance for your help,

James

Originally Posted by jsab500

Hi, is it possible to solve the equation

y = alnx + bx + c?

I made it myself as it seems to best model something, and want a computer program i'm writing to be able to calculate x. Is this actually possible?

Thanks very much in advance for your help,

James

Do you want to solve for x in terms of y?

An exact solution will require using the Lambert W-function.

Yes in terms of y.

How would i go about doing that?

Thanks

Originally Posted by jsab500

Yes in terms of y.

How would i go about doing that?

Thanks

Are you familiar with the Lambert W-function?

What's wrong with using a numerical procedure to get an approximate value of x for a given value of y .....?

nothing's wrong with it, but if there was a way to just get x = whatever, it would be significantly simpler. I'll have a look at that Lambert-W function.

Thanks a lot