## Comment on this statement.

Short proofs and reasons (Recall that Q is an orthogonal matrix and QTQ=I) (a) In one line explain why the determinant of Q is non-zero. (b) If Q is nxn and x is any nx1 vector, prove that, Qx.Qy = x.y (dot products) (c) If l is an eigenvalue of A, prove that l+c is …