Question:
Writing a_1,a_2,b as column vectors
Suppose L_1 is the line through the origin in the direction of a_1, and L_2 is the line through b in the direction of a_2. To find the closest points x_1a_1 and b + x_2a_2 on the two lines, write down the two equations for the x_1 and x_2 that minimize ||x_1a_1 - x_2a_2 - b||. Solve for x if a_1 = (1,1,0), a_2 = (0,1,0), b = (2,1,4).