Some typos and corrections on Problem Set 4:

problem 8:

Actually, the period is pi, not 2pi

You may take the special case a = "1.5" in this problem, if you want.
Also:

                             the magnitude of
(a) that one characteristic --> that one characteristic
                                    ^

        of magnitude
(b) must be < 1          (and the product is exp(-pi/2) since period is pi/2)
           ^

(c) clarification: you are asked to find (approximately) a second solution
    NUMERICALLY, not in "closed form"

Actually, this part should be deleted - next set has a better problem that
does it in closed form.

problem 11:

(a) should be "evaluated at t=0".