"Nasser M. Abbasi" schrieb:   
   >   
   > And here where is "hangs" for long time.  It is trying to find det   
   > of this matrix M   
   >   
   > [...]   
   >   
      
   Although this is a bad way to implement apart(), I have computed the   
   12x12 determinant on Derive out of curiosity:   
      
   DET([[b^10,0,b^9,0,0,0,0,0,0,0,0,0],[10*a*b^9,b^10,9*a*b^8,b^8,0~   
   ,0,0,0,0,0,0,0],[45*a^2*b^8,10*a*b^9,36*a^2*b^7,8*a*b^7,b^7,0,0,~   
   0,0,0,0,0],[120*a^3*b^7,45*a^2*b^8,84*a^3*b^6,28*a^2*b^6,7*a*b^6~   
   ,b^6,0,0,0,0,0,0],[210*a^4*b^6,120*a^3*b^7,126*a^4*b^5,56*a^3*b^~   
   5,21*a^2*b^5,6*a*b^5,b^5,0,0,0,0,0],[252*a^5*b^5,210*a^4*b^6,126~   
   *a^5*b^4,70*a^4*b^4,35*a^3*b^4,15*a^2*b^4,5*a*b^4,b^4,0,0,0,0],[~   
   210*a^6*b^4,252*a^5*b^5,84*a^6*b^3,56*a^5*b^3,35*a^4*b^3,20*a^3*~   
   b^3,10*a^2*b^3,4*a*b^3,b^3,0,0,0],[120*a^7*b^3,210*a^6*b^4,36*a^~   
   7*b^2,28*a^6*b^2,21*a^5*b^2,15*a^4*b^2,10*a^3*b^2,6*a^2*b^2,3*a*~   
   b^2,b^2,0,0],[45*a^8*b^2,120*a^7*b^3,9*a^8*b,8*a^7*b,7*a^6*b,6*a~   
   ^5*b,5*a^4*b,4*a^3*b,3*a^2*b,2*a*b,b,0],[10*a^9*b,45*a^8*b^2,a^9~   
   ,a^8,a^7,a^6,a^5,a^4,a^3,a^2,a,1],[a^10,10*a^9*b,0,0,0,0,0,0,0,0~   
   ,0,0],[0,a^10,0,0,0,0,0,0,0,0,0,0]])   
      
   a^20*b^45   
      
   and found this exercise to take 10 milliseconds or so on a modern   
   computer.   
      
   Martin.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)