9/15/2016 Minor changes for clarity to the text before example 13.2.7
(late transcendentals 15.2.7) and to the example.
9/25/2016 Added theorem 14.3.5 (16.3.5)
10/ 9/2016 Minor corrections in 14.5 & 14.7 (16.5 & 16.7)
equation -> vector function in a few exercises in 14.5
added one displayed equation in example 14.7.2