华中师范大学专用
µ
1
=
cosxdx1
2du1 u 1+u2
=2
du
=
1 u11
1 u+
1+udu= ln|1 u|+ln|1+u|+C
=ln 1+u 1 u
+C
1+u2=ln +2u 1 u +C
=ln 1+u2
2u 1 u2+1 u2
+C
=ln|secx+tanx|+C.
ؽȩúªµ(1)
11x
(x2+1)2dx=2arctanx+2(x2+1)
+C.
(2)
x2
(x2+1)2dx=12arctanx x2(x2+1)+C.(3) x(x+1)dx=1
12(x+1)d(x2
+1)= 12(x+1)+C.
(4)
x3
(x2+dx
= 1 1)2
12x2dx2
+1
=
x22(x+1)+
x
x+1dx= x2+1ln(x22(x+1)2+1)+C.(1) y²:
6
(0.6)
(0.7)
(0.8)(0.9)
(0.10)