LOS M^TODOS DE INTEGRACION 
149 
/ , sen x 
d = tg x 
COS X 
36. f sec 2 a x d x = — f sec 2 a x d a x 
J a J 
= — tg a x 
a ° 
37. f cosec 2 x d x=/sec 2 (90° — x) dx 
38. /■ 
39. 
sen x 
cos x 
J sen^x 
= — tg (90° — x) = - cot x 
d x = — / cos— 1 x d cos x 
cos— 1 x = sec x . 
d x = / sen— 2 x d sen x 
= — sen— 1 x= — cosec x 
40. 1™ — — — dx= 1 
j sen x cos x I sen x 
d x 
cos^ x 
cos x 
d tg x 
tgx 
--= L tg x 
Valparaiso, Febrero 23 de 1909. 
Carlos Wargny. 
