OpenEuphoria

Re: Algebra problem

• Posted by Erik-Jan van Kampen <e.vankampen at student.tudelft.nl> Jul 07, 2005
• 639 views

Derek Parnell wrote:
> 
> My high school algebra has deserted me 
> 
>  Given the formula 
> 
>    A^b + Cb = d
> 
> how do I solve for 'b'?
> 
> -- 
> Derek Parnell
> Melbourne, Australia
> 

Hi Derek,

 From the Matlab 6.5 Symbolic Toolbox:

>> solve(A^b+C*b-d,b)
 
ans =
 
-(lambertw(log(A)/C*exp(d*log(A)/C))*C-d*log(A))/log(A)/C
 
>> help lambertw

 LAMBERTW Lambert's W function.
    W = LAMBERTW(X) is the solution to w*exp(w) = x.
    W = LAMBERTW(K,X) is the K-th branch of this multi-valued function.
    Reference: Robert M. Corless, G. H. Gonnet, D. E. G. Hare,
    D. J. Jeffrey, and D. E. Knuth, "On the Lambert W Function",
    Advances in Computational Mathematics, volume 5, 1996, pp. 329-359.
    Also available from:
    http://pineapple.apmaths.uwo.ca/~rmc/papers/LambertW/index.html

Regards,
          Erik-Jan