Exercises XVII. (See p. 263 for the Answers.)
(1) Find when .
(2) Find .
(3) Find .
(4) Find .
(5) Find .
(6) Find .
(7) Find ; find .
(8) Find .
(9) Find .
(10) Find .
(11) Find .
(12) Find .
(13) Find .
(14) Find .
(15) Find .
(16) Find .
(17) Find .
(18) Find .