Richard Fateman schrieb:   
   >   
   > On 7/17/2016 4:17 PM, Dr Huang wrote:   
   > > what is result of integrate(x*f(x),x)=?   
   > > wolfram, sagemath, sympy, integral calculator cannot. can your   
   > > software ?   
   >   
   > sure.   
   >   
   > Maxima returns the result   
   > integrate(x*f(x),x)   
   >   
   > Looks right to me.   
   >   
   > now if you declare that the antiderivative of f(x) is F(x), then   
   > one can integrate(x*f(x^2),x)   
   > and get F(x^2)/2   
   >   
      
   Using Derive 6.10:   
      
   f(x):=   
      
   INT(x*f'(x^2), x)   
      
   f(x^2)/2   
      
   Here f'(x^2) is short for SUBST(DIF(f(x), x), x, x^2), even though the   
   system cannot simplify   
      
   f'(x^2) = SUBST(DIF(f(x), x), x, x^2)   
      
   f'(x^2) = SUBST(f'(x), x, x^2)   
      
   down to true. And so my bug list has grown by another entry.   
      
   Martin :(.   
      
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