[题目]计算 (int )_(1)^+infty dfrac (arctan x)({x)^2}dx

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

[题目]求 int dfrac (arctan {e)^x}({e)^2x}dx

(int )_(-infty )^+infty (x)^2(e)^-a(x^2)dx=dfrac (1)(2)sqrt (dfrac {pi )({a)^3}}

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

[题目]-|||-(int )_(2)^+infty dfrac (dx)((x+7)sqrt {x-2)}= __

计算int dfrac (arctan sqrt {x)}(sqrt {x)(1+x)}dx计算

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

(int )_(-infty )^+infty dfrac (dx)({x)^2+2x+2}..

计算(int )_(0)^+infty dfrac (dx)({x)^2+4x+3}的值是A (int )_(0)^+infty dfrac (dx)({x)^

()-|||-(2) (int )_(-infty )^+infty dfrac (2x)(1+{x)^2}dx=lim _(aarrow +infty )(i