Given the points A and B, for the vector AB, find: (a) magnitude (b) direction cosines (c) the unit vector AB in the direction of AB (d) draw the vector in the system of coordinates. A(8, 1, 2), B(1, 2, -1). 2. Given the points A, B, C, D, calculate: (a) the angle B of the triangle ABC (b) the area of the triangle ABC (c) the median BE of the triangle ABC (d) the height AH of the triangle ABC (e) the volume of tetrahedron ABCD (f) the point E so that ABCE is a parallelogram. A(-3,-1, 1), B(-9, 1, -2), C( 3, -5, 4), D(-7, 0, -1). 3. A parallelogram is built on the vectors a and b such that a=3p-4g, b=p+29; p=3, |a|=2, < (p)= Find the length of its diagonals. 3