HW4 Prob 3a formula correction

The formula in the book for problem 3a is incorrect. It should be be replaced with:

$y_k=C{A}^k{x}_0+\sum _{i=0}^{k-1}C{A}^{i}B{u}_{k-1-i}+D{u}_k$

--Julia Braman 08:19, 23 October 2007 (PDT)