c is  8 
      and its value at 3 is: 8
      and its derivative with respect to x is:  0 
x is  x 
      and its value at 3 is: 3
      and its derivative with respect to x is:  1 
simple is ( 123.45  *  y )
     and its value at 3 is: 370.35
     and its derivative with respect to y is:  123.45 
     and its derivative with respect to x is:  123.45 exit 0