104 
MEMORIAS CIENTIFICAS I LITERARIAS 
/ ',t V a— x a 
y = Va x — x 1 2 arc sen — ■- — 4- 
1 a-fx 
]/ 2 J a + x 
La nueva integracion es de inmediata integracion. 
25. 
/ 
x 
arc sec 
Sea 
u = arc sec 
1 + x 2 
1— x 2 
. . d u = d arc sec z = 
d z 
z Jlf-- 1 
Lz=y [L (l + xp )— -L ( (1 — x-i ) | 
dz 1 [ 2x 2x \ , 
z 2 1 + x 2 1 - x 2 / 
, x. d x 
d Z = = 
x/l + x 2 . x/ (1 — x 2 ) 3 
X 
, J 1 + X 2 */ (1 — X 2 )3 
d U = ' ,-r . 
■s/l+X 2 -]/l+x 2 _ 
XTi'-x* ' v i - x 2 
X (1 — X 2 ) 
X ( 1+x 2 ) (1— x 2 )Y 
1 
( 1 + x 2 ) ( 1 + x 2 )4 
