multivariable control book

Hi M. Skogestad,

    My name is Patrick Cadotte and I'm a graduate student from McGill. I
don't want to bother you too much with such a little thing, but there's
a miscalculation of the matrix delta in equation 8.72 on page 311. The
result should be [.2 -.1 ; .2 -.1] or [.2 .2;-.1 -.1]' instead of [.2
.2;-.1 -.1]. Otherwise, the determinant of I-M*delta is not equal to
zero. It's not that important, but it might interrest you in the case
you're doing another edition.

Patrick