Chapter 4 - Integration - 4.2 The Indefinite Integral - Exercises Set 4.2 - Page 279: 26

$$ - \cos y + C$$

$$\eqalign{ & \int {\frac{{dy}}{{\csc y}}} \cr & {\text{basic trigonometric identity csc}}\theta = \frac{1}{{\sin \theta }} \cr & \int {\frac{{dy}}{{\csc y}}} = \int {\frac{{dy}}{{1/\sin y}}} \cr & = \int {\sin y} dy \cr & {\text{use integration formula from table 4}}{\text{.2}}{\text{.1}} \cr & = - \cos y + C \cr} $$