Notice that {[1 -2 1 -1], [ 2 1 -1 1]} is an orthogonal basis for U.
Writing Y with respect to this basis is (-1,1)
so (-1,1) Z = 0
so Z can be span{(1,1)}
so Z can be span {(3,-1,0,0)}
Last edited by badgerigar; December 12th 2007 at 03:07 AM.
Reason: forgot math tags