In the uploaded worksheet, using "solve" takes too long to evaluate and won't answer, while "fsolve" will only simply rewrite the equation. What am I missing?
 1-parasitic.mw

This may be a very elementary question, but my searches on the topic have been unsuccessful, so I have to ask here. I've plotted a function using plot3d, and I want to find the exact value of the two variables for which the function equals a certain value. How can I find this point on the plot in the easiest way?
As an example, I have 

And I want to find the points for which abs(zIT)-50=0. zIT is a function of L & C defined previously.

After waiting about six hours for the worksheet to be executed, I finally lost hope and stopped it. (My CPU usage was stuck on 100% the whole time and I almost ran out of memory) Is this evaluation time normal and should I have waited longer, or is there a problem with my worksheet? (I'm uploading it here) Or is it possible that the equation cannot be solved by Maple at all?

parasitic.mw

I have written the following coade in Maple:
r := 50;
l1 := 0.2742e-10;
s := I*w;
l := (-1.342110665*10^22*c^2*(Pi^4)-4.225000000*10^25*c^2*(Pi^2)+2.316990000*10^11*c1*(Pi^2)-1)/(-1.342110665*10^22*c^2*c1*(Pi^4)-7.140250000*10^43*c^2*c1*r^2*(Pi^4)+1.957856550*10^33*c^2*(Pi^4)+9.789282750*10^32*c*c1*(Pi^4)-1.690000*10^22*c*(Pi^2)-4.22500*10^21*c1*(Pi^2));
z1 := (c*l1*s^2+1)/(c*s);
z2 := l*s/(c1*l*s^2+1);
h := (z1+2*z2)*((z1+2*r)*(z1+3*z2)/(2*r)-2*z2)/z2-(1/2)*z2*(z1+2*r)*r;
f := h*(z1+3*z2)/z2-(z1+2*r)(2*r)*(z1+3*z2)+2*z2;
gain := 2*z2/f;
a := abs(gain);
d := diff(a, w);
s := subs(w = 2*pi*0.325e11, d)
Now, I have a function named "s" which I want to set to zero, and calculate the relationship between variables c & c1 in order to achieve this. How should it be done?
Thanks.