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
.