"Nasser M. Abbasi" schrieb:   
   >   
   > Hello Martin:   
   >   
   > Rubi 8.1 on Mathematica 10.1 returns partial result:   
   >   
   > Clear[x];   
   > Int[ArcCos[x^2 - Sqrt[1 - x^2]], x]   
   >   
   > x*ArcCos[x^2 - Sqrt[1 - x^2]] +   
   >   2*Int[x^2/Sqrt[1 - (x^2 - Sqrt[1 - x^2])^2], x] +   
   >     Int[x^2/(Sqrt[1 - x^2]*Sqrt[1 - (x^2 - Sqrt[1 - x^2])^2]), x]   
   >   
   > Mathematica 10.1 and Maple 15 return unevaluated.   
   >   
      
   But the Wolfram integrator can still do it! Mathematica is evidently   
   entering its second childhood.   
      
   Martin.   
      
   --- SoupGate-Win32 v1.05   
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