(1) Consider the the points A = (2, 1, 1), B = (-1, 0, 1) and C = (1, 1, 3) in R." . They define a triangle. (a) Let's find vectors determining this triangle. Compute v = BA = A - B and w = BC = C - B. (b) Use the appropriate Gram determinant associated with those two vectors to find the area of our triangle. (c) Now compute the cross product v X w and use it to find the area of our triangle