Calculus and Vectors

20. Determine the angle between a@ = (5, 3, 0) and b =(-1,0,8) 21. The vertices of a quadrilateral are A = [0, 3,5],B = [-3,-1,17], = [4,-3,15] & D =[7,1,3]. Prove that ABCD is a parallelogram. o z+1 k-1 x=1 -2 22. Determine the value of & for which the direction vectors of the lines " = T x+3 Z _2 = I' y = 1 are perpendicular. and