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

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

[题目] int dfrac (x)(sqrt {1-{x)^2}}dx

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

[题目] int dfrac (xarctan x)(sqrt {1+{x)^2}}dx

[题目]-|||-int (dfrac (3)(1+{x)^2}-dfrac (2)(sqrt {1-{x)^2}})dx

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

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

(({int )_(-2)^2}(x-2)sqrt (4-{x)^2}dx

(int )_(-2)^2(x-2)sqrt (4-{x)^2}dx

求不定积分int dfrac (1)(2x)sqrt (ln x)dx=（）.int dfrac (1)(2x)sqrt (ln x)dx=int dfrac