Problem 3a -- Formula correction

The formula given in problem 3a is incorrect. It should be be replaced with:

$y_{k}=CA^{k}x_{0}+\sum _{i=0}^{k-1}CA^{i}Bu_{k-1-i}+Du_{k}$

--Mary Dunlop 19:29, 17 October 2006 (PDT)