894 ‘ 
MEMORIAS CIENTIFICAS I LITERAKIAS 
COS X 
senx \ a cosx+bsenx 7 a"+b’^ 
+ — T- 
COS X 
b'^cos X — ab sen x 
(a‘^ -|- b^) (a cos x -f b sen x) 
b cos X — a sen x a 
+ 
a^+b^ acosx + bsenx a^+b' 
■■■/ 
dx 
d sen x + a dcosx a 
+ — s — r^iax 
a + btgx a^ +b^ 7 V a cos x + b sen X a-+b'; 
rjdx 
1 
a" + b^ 
I b L (a cos X + b sen x) + a x ] 
(Brahy, 28 ) 
22 . 
d X 
a sen x + b cosx 
Primer metodo. Hagamos 
a = rsena^ b = rcosct: 
[• 
J r sen a 
dx 
sen X + r cos a cos x 
f/- 
dx 
cos (x — a) 
Ltg 
x + a 
l/a'+b" 2 
(Serret. 79 ) 
"i/a^ + b^ 
Sequndo metodo. Introduzcamos 1 = -^===x: 
^/a* + b^ , 
