solve implicit function



Hi,
I would like to solve an equation with maximas's solve-function. The problem 
is that it is an implicit function and the solve-function give no result. How can I 
solve this Problem. 


(%i1)  eqn3: 1/w*sqrt(Rs(rho_c+0.2*Rs*h^2))*coth(sqrt(Rs/(rho_c+0.2*Rs*h^2))*d)-Rc;

(%i2) Rs: 2.53;

(%i3) Rc: 0.395;

(%i4) h: 1.4e-6;

(%i5) d: 49e-6;

(%i6) w: 100e-6;

(%i7) solve(eqn3,rho_c);


Thanx, Lars
____________________________________________________________________
Psssst! Schon vom neuen WEB.DE MultiMessenger geh?rt? 
Der kann`s mit allen: http://www.produkte.web.de/messenger/?did=3123

-------------- next part --------------
A non-text attachment was scrubbed...
Name: lars b?ttcher.vcf
Type: text/x-vcard
Size: 154 bytes
Desc: not available
Url : http://www.math.utexas.edu/pipermail/maxima/attachments/20090427/45cce5cc/attachment.vcf