Hi.

I am quite clueless about the following problem and need help on where to start.

given

y =

[1 2]

[3 4]

x1 =

[1,0]

[0,0]

x2 =

[1,0]

[0,1]

(these are all 2x2 matricies by the way, not vectors).

Record the orthogonal decomposition of Y obtained by orthogonally projecting Y onto L(X1,X2).

I have no idea where to start on this.