# math

posted by
**V**
.

Let A=

[7 -4 4]

[-4 5 0]

[4 0 9]

a) Orthogonally diagonalize A

b) Use answer from a) to construct a spectral decomposition for A.

c) Suppose that x=[1 2 1] and let u be the eigen vector from a) corresponding to the largest eigen-value of A. If W=Span {u}, then use b) to decompose x into a sum of vectors, one in W and the other in W¡Í.