On 10/31/99, belhajse asks about Q5 of MA322-005,11 Section 4.1 and 4.2 (Oct 29): I don't see why it's false? Response: These planes intersect in a line. Orthogon subspaces intersect only in the O vector.

On 10/31/99, belhajse asks about Q8 of MA322-005,11 Section 4.1 and 4.2 (Oct 29): Can you tell me how you got this result? Response: Find the null space matrix A of the equation. Then construct the projection matrix A(A^TA)^(-1)A^T from that. Then multiply that by the point to be projected.

On 11/2/99, kendigbr asks about Q13 of MA322-005,11 Section 4.1 and 4.2 (Oct 29): WHY CAN'T IT BE, IS THIS AN ALWAYS QUESTION?? Response: Don't shout. Yes, this is an always question. The statement is false if you can find a single instance where it is false.

On 11/2/99, kendigbr asks about Q19 of MA322-005,11 Section 4.1 and 4.2 (Oct 29): CAN'T FOLLOW AFTER FIRST EQUALITY OF PROBLEM! Response: Use the associatively of matrix multiplication and the properties of inverses to see that the algebra holds true.

On 10/29/99, claybomi asks about Q13 of MA322-005,11 Section 4.1 and 4.2 (Oct 29): i don't understand! Response: Projection matrices have the property that they are their own square, but matrices with that property do not have to be projection matrices.

On 10/29/99, claybomi asks about Q8 of MA322-005,11 Section 4.1 and 4.2 (Oct 29): how can this be? Response: Be more specific.