> int(f'(x),x) = f(x) ?  isn't this what FTOC says?   
      
      
   Not exactly, you also need to know (prove) f is contionus,   
   but that's a different story.   
   ----   
   In how I see "int(f'(x),x)=f(x)"   
   "int(f'(x),x)=f(x)" => f has to be derivable in its set of definition   
   (otherwise f'() would not exist)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)