> with(linalg):
Warning, the protected names norm and trace have been redefined and
unprotected

> Formfunktionen:=matrix(1,3,[N[1],N[2],N[3]]);

               Formfunktionen := [N[1]    N[2]    N[3]]

> J:=multiply(transpose(Formfunktionen),Formfunktionen):
> Massenmatrix:=Int(rho*evalm(J),V);

                     /     [      2                            ]
                    |      [  N[1]       N[1] N[2]    N[1] N[3]]
                    |      [                                   ]
   Massenmatrix :=  |  rho [                   2               ] dV
                    |      [N[1] N[2]      N[2]       N[2] N[3]]
                    |      [                                   ]
                    |      [                                2  ]
                   /       [N[1] N[3]    N[2] N[3]      N[3]   ]

> N[1] := xi -> 1-3*xi+2*xi^2;

                                                 2
                    N[1] := xi -> 1 - 3 xi + 2 xi

> N[2] := xi -> 4*xi*(1-xi);

                     N[2] := xi -> 4 xi (1 - xi)

> N[3] := xi -> xi*(-1+2*xi);

                     N[3] := xi -> xi (-1 + 2 xi)

> p := map(int,J(xi),xi=0..1);

                          [                 -1 ]
                          [2/15    1/15     -- ]
                          [                 30 ]
                          [                    ]
                     p := [1/15    8/15    1/15]
                          [                    ]
                          [ -1                 ]
                          [ --     1/15    2/15]
                          [ 30                 ]

> Massenmatrix := (rho*A*l)/30*evalm(30*p);

                                         [ 4     2    -1]
                                         [              ]
            Massenmatrix := 1/30 rho A l [ 2    16     2]
                                         [              ]
                                         [-1     2     4]

> 
> 
