newbie | implicit differentiation



  GIven a polynmial in multiple variables, I'm looking for the Maxima 
equivalent of the Maple function implicitdiff.

Say

f:=lamda^2-lambda*c-a*lambda+a*c-b^2=0

To implicitly differentiate lambda with respect to  in Maple, I'd simply 
enter

implicitdiff(f,lambda,c)

yielding

  (a-lambda)/(-2lambda+c+a)


There is no straight equivalent in Maxima for the implicitdiff command 
in Maple (not that I can find). Did find implicit_derivative, but I 
can't seem to make out exactly what it does (since there are no examples 
I could find that demonstrated it). Google didn't seem to help here much 
either.

So, how does one do simple implicit differentiation in Maxima? Is there 
a simple 'single command' to do the trick, or do I have to break up the 
problem in pieces, somehow?

Pointers to the obvious appreciated.

Thanks very much in advance.