On Sunday, May 3, 2020 at 11:07:50 PM UTC+10, clicl...@freenet.de wrote:   
   > samuel.thomas.blake@gmail.com schrieb:   
   > >   
   > > Can you please double check those solutions?   
   >   
   > All four?   
   >   
   > Martin.   
      
   My bad (misreading ArcTan and ArcTanh in your solutions). In mathematica they   
   are   
      
   In[1081]:=   
   D[ArcTanh[((x + I)/(1 - 6*x^2 + x^4)^(1/4))] +   
      ArcTan[((x + I)/(1 - 6*x^2 + x^4)^(1/4))] +   
      ArcTanh[((x - I)/(1 - 6*x^2 + x^4)^(1/4))] +   
      ArcTan[((x - I)/(1 - 6*x^2 + x^4)^(1/4))], x] // Simplify   
      
   Out[1081]= (-3 + x^2)/((-1 + x^2) (1 - 6 x^2 + x^4)^(1/4))   
      
   In[1082]:=   
   D[-ArcTanh[((x + I)/(1 - 6*x^2 + x^4)^(1/4))] +   
      ArcTan[((x + I)/(1 - 6*x^2 + x^4)^(1/4))] -   
      ArcTanh[((x - I)/(1 - 6*x^2 + x^4)^(1/4))] +   
      ArcTan[((x - I)/(1 - 6*x^2 + x^4)^(1/4))], x] // Simplify   
      
   Out[1082]= -((1 + x^2)^2/((-1 + x^2) (1 - 6 x^2 + x^4)^(3/4)))   
      
   Sam   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)