Lösungen/Solutions/
B1S2Ue/Ex4

L = Lektion/ Leçon   -- Sprechstunde / heures de consultation
W = Work / Arbeit / Travail
A  =Anhang/  Annexe / Appendice

vecLen[a_] := Sqrt[a . a];
look[a_] := {a, N[a]}

Ueb/Ex 1      W

a = {1, 2, -1};
b = {-2, 4, 3};
c = {0, 1, 5};
A1 = 1/2 vecLen[Cross[a, c]];
A2 = 1/2 vecLen[Cross[a - b, c - b]];
A3 = 1/2 vecLen[Cross[b, c]];
A4 = 1/2 vecLen[Cross[a, b]];

look[A1]

look[A2]

look[A3]

look[A4]

A = A1 + A2 + A3 + A4;  look[A]

Remove[V]

V[a_, b_, c_] := 1/6  Cross[a, b] . c

look[V[a, b, c]]

Ueb/Ex 2      W

r01 =  {1, 2, -1};   r02 = {5, -3, 
        6};
a = {-2, 4, 3};             b = {0, 1, 
        5};
dmin = 
        V[a, b, r02 - r01] / 
          vecLen[Cross[a, b]];
look[dmin]