Precalculus / 
Cohen, David ; Lee, Theodore B. ; Sklar, David 
 - 7th ed. 
 - USA :  Cengage Learning,  2017. 
 - xvi, v.p. col.ill. ; 25.4cm. 
<br/><br/>Includes: answers, index 
<br/><br/><label>ISBN: </label>9781305663107 
<br/><br/><label>Dewey Class. No.: </label>C 515 C678 2017