c is 
      and its value at 3 is: 8
      and its derivative with respect to x is: 
x is 
      and its value at 3 is: 3
      and its derivative with respect to x is: 
simple is (*)
     and its value at 3 is: 370.35
     and its derivative with respect to y is: ((*)+(*))
     and its derivative with respect to x is: ((*)+(*))exit 0