Sorry to botter you again but this I can't solve. I really need your help
I posted it before but the format of the matrix was crappy
Let A = (1 -2
-1 2
0 3
2 5)

and b = ( 3
1
-4
2)

(a) Find a least-squares solution of Ax = b.
(b) Find the orthogonal projection of b onto the column space of A.
(c) Compute the least-squares error ( in the solution of part ( a )).
Thank you!