Show that the poin-2) and (1,-4) are con-cyclic.

Show that the points (0,-2) , ( -1,1),(-2,4) are collinear.

Show that the points quad (1,7),(4,2),(-1,-1) and (-4,4) are the vertices of a square.

Show that the points A(2,3,-4) B(1,-2,3) and are collinear.

" (c) Show that the points "(3,-2,4),(1,1,1)" and "(-1,4,-2)" are collinear."

For what value ofk,the points (0,0),(1,3),(2,4) and (k,3) are con-cyclic :

Show that the points (-2,4,1),(-1,5,5),(2,2,5) and (1,1,1) are the vertices of a square.

Show that the points (1, 2, 3), (-1, -2, -1), (2, 3, 2) and (4, 7, 6) are the vertices of a parallelogram.

Show that there con be no net charge in a region in which the electric field is uniform at all points.

Show that the points (4,7,8),(2,3,4),(-1,-2,1) ,(1,2,5) are the vertices of a paralelogram.

Show that points (1,7),(4,2),(-1,-1) and (-4,4) are vertices of a suare.