Math 252 HW#07 sec. 4.4 #1 Maple Work

We start by loading the "linalg" package:

  with(linalg):

Part (a):

  F:=vector([12*x*y+y*z,6*x^2+x*z,x*y]);
                      [                 2           ]
                 F := [12 x y + y z, 6 x  + x z, x y]
  curl(F,[x,y,z]);
                              [0, 0, 0]
Therefore the vector field is conservative.


Part (b):

  F:=vector([z*exp(x*z),0,x*exp(x*z)]);
                   F := [z exp(x z), 0, x exp(x z)]
  curl(F,[x,y,z]);
                              [0, 0, 0]
Therefore the vector field is conservative.


Part (c):

  F:=vector([sin(x),y^2,exp(z)]);
                           [         2        ]
                      F := [sin(x), y , exp(z)]
  curl(F,[x,y,z]);
                              [0, 0, 0]
Therefore the vector field is conservative.


Part (d):

  F:=vector([3*x^2*y*z^2,x^3*z^2,x^3*y*z]);
                        [   2    2   3  2   3    ]
                   F := [3 x  y z , x  z , x  y z]
  curl(F,[x,y,z]);
                         [  3       2       ]
                         [-x  z, 3 x  y z, 0]
Therefore the vector field is not conservative.


Part (e):

The domain is not simply connected, therefore the curl test is not valid. However, just out of curiosity, let's try it:
  F:=vector([2*x/(x^2+y^2),2*y/(x^2+y^2),2*z]);
                        [     x          y        ]
                   F := [2 -------, 2 -------, 2 z]
                        [   2    2     2    2     ]
                        [  x  + y     x  + y      ]
  curl(F,[x,y,z]);
                              [0, 0, 0]
In this case, the curl is zero, but that doesn't tell us anything.


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Revised 22 March 1999 by John Hebron.