How can I plot $\kappa(\epsilon_{dd},\lambda)$ this transcendental equation? $$3\kappa \epsilon_{dd}\left[\left(\frac{\lambda^2}{2}+1\right)\frac{f_s(\kappa)}{1-\kappa^2}-1\right]+(\epsilon_{dd}-1)(\kappa^2-\lambda^2)=0 $$ where $\lambda=1,2,3,4$ and $$f_s(\kappa)=\frac{1+2\kappa^2}{1-\kappa^2}-\frac{3\kappa^2 artanh \sqrt{1-\kappa^2} }{(1-\kappa^2)^{3/2}}. $$ My original problem is not that, but it's similar. If you help me with this, maybe I can solve mine. Here are the codes of equations: fs[kappa_] := (1 +3 kappa^2)/(1 - kappa^2) - (3 kappa^2 ArcTanh[ Sqrt[1 - kappa^2]])/(1 - kappa^2)^(3/2) 3 kappa edd (((lambda^2/2) + 1) fs[kappa]/(1 - kappa^2) - 1) + (edd - 1) (kappa^2 - lambda^2) == 0 [![Original plotting][1]][1] [1]: https://i.sstatic.net/jsqWw.jpg