. (10 points) 1 2 2 1 Letal= 2 ,a2= 2 .032 1 ,andb= 0 2 1 2 0 (a) Compute the projection matrices P1 and P2 onto the lines through an and a2. Multiply those matrices and explain geometrically why P1P2 is what it is. (b) Project b = (1,0,0) onto the lines through (11 and a2 and also onto 03. Add up the three projections 191 + p2 + 193. (c) Find the projection matrix P3 onto a3. Verify that P1 + P2 + P3 = I. This means that the basis a1, a2, a3 is orthogonal! Why