LOS MJ6TODOS DE 1NTEGKACION 
129 
2. /x n .e ax dx. Sea 
u = x n 
. • . du = n x 11_ t dx 
d v = e a x d x 
1 
y = — x n e a x 
a 
— f x n — 1 e a x d x 
a J 
l. Sea a = l ? 
/ x n e x d x =x n e x — n / x n — 1 e x d x 
II. Sea n = 1 
/ x e x d x=x e x — e x 
III. n=2: / x 2 e x d x=x 2 e x — 2 j x e x d x 
=x 2 e x — 2 (x e x — e x ) 
En jeneral: 
IV. / x» e x d x=e x [ x n — n x n ~ i-|~ n ( n — l)x n ~ 2 — ... ] 
V. Sea n=4: 
f e a X x 4 d x = e ax 
12x* 
a 3 
24 x 4! \ 
a 4 4 a 5 ] 
VI. Sea n—h, a= — 1 
(x 5 -f-5 x 4 +20 x ;3 -f-60 x 2 -j-120x-j-120) 
tomo CXX1V 
9 
