Question 4: July 2020 a) Find the unit vector that is in the opposite direction to the vector u = (2, 1, 3) . b) Given the points P(5, 4, -6), Q(6, 6, -3) and R(11, 12, 4) where u = PQ and v = QR. Determine whether u and v are orthogonal. Give a reason for the answer. c) Compute a volume of parallelepiped that is determined by the vectors a = (2, 0, 1) , . b = (1 6, -7) . and c = (1 1 3). Question 5: Jun 2019 a) Let u = (2,-1,1) and v =(1,2,-3) . Find the value of B if u + B(0,0,1) and V - B(10,0) are orthogonal. b) Find the value of m if the volume of the parallelepiped with vertices A(1,1,1) and B(m, 1,1), C(3,3,1) and D(-1,-1,-1) is 4