Errata for the 3^rd printing

*Page 91, line 4 of second paragraph: (1571□630) should read (1571-1630).

*Page 166, Figure 5.3(b): The label τ on the horizontal axis needs to move about 3 mm to the right to its tick mark. (This was correct in the first printing.)

*Page 362, Problem 9.13: “is well approximated by tan α = ” should read

“is given by sin α = ”

*Page 550, line 2 of the text: Put a dot over the q in ∂q_i.