L0« METODOS DE INTEGRACION 
621 
20. /e^ dx (3x-’ + x'^ — 1) = /e^ [ (x’^ — l) + 3x^] dx 
= / [ (x'" — 1) dx+ e.x 3xMx ] 
= /[e^ (x®~ 1) dx + e^ d (x® — 1) ] 
== / [ (x-"^— 1) d ex 4- d (x^— 1) ] 
= / (u d V + V d 11 ) = / d u V = uv 
— / (x'" — 1) e.x (Francoeur, 374). 
fl~T dx = [- ^ = arc tg 
jl+e2x j i_)_(ex)^ 
(Briot, II; 195) 
Logaritmicas. 
22 
LxdLx = — L‘^x. 
23. 
L^^x 
X 
dx 
("De Comberousse; IV, 684) 
Ln+i X 
L"xdLx 
n + 1 
24 . 
(H. CoX; 39) 
j yi+Lx _y- (i_^Lx)-Td(l+Lx) 
~ L(l + Lx) T (J. Bertrand; II; 2) 
