(9) int dfrac (x{e)^arctan x}({(1+{x)^2)}^dfrac (3{2)}}dx ;

int dfrac ({x)^3}({(1+{x)^2)}^2}dx=A.int dfrac ({x)^3}({(1+{x)^2)}^2}dx=B.int df

(5) int dfrac (arctan x)(1+{x)^2}dx= __

2.计算下列不定积分：(9)int dfrac (x{e)^arctan x}({(1+{x)^2)}^dfrac (3{2)}}dx.2.计算下列不定积分：(

( 单选题 ) int dfrac ({e)^x}(1+{e)^2x}dx=_________int dfrac ({e)^x}(1+{e)^2x}dx=int

(int )_(0)^1arctan dfrac (x)(2)dx=()(int )_(0)^1arctan dfrac (x)(2)dx=()(int )_(

7.不定积分 int dfrac (arctan x)({x)^2(1+(x)^2)}dx= __

(3) int dfrac (1)({(1+{x)^2)}^dfrac (3{2)}}dx;

int dfrac (ln x)({(1+{x)^2)}^3/2}dx; ;

int dfrac ({x)^3}(sqrt {1+{x)^2}}dx,

[例3] (int )_(0)^+infty dfrac (x{e)^-x}({(1+{e)^-x)}^2}dx