B: (Xgt X)=(int )_(-infty )^xf(x)dx-|||-C: (int )_(-infty )^+infty f(x)dx=1 D: (+infty )=1

(int )_(-infty )^infty (e)^xg(x+1)dx=_________._________.

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

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

4.下列结论正确的是 ()-|||-(A) (int )_(-infty )^+infty dfrac (x)(1+{x)^2}dx=0 (B) (int )_

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

(2)int_(-infty)^+infty(dx)/(x^2)+2x+2;(2)$\int_{-\infty}^{+\infty}\frac{dx}{x^{2

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

1.讨论下列无穷积分是否收敛?若收敛,则求其值:-|||-(1) (int )_(0)^+infty x(e)^-(x^2)dx;-|||-(2) (int )

广义积分int_(1)^+infty(1)/(x^2)dx=（）A. 0B. 1C. -1D. 3

【题目】-|||-设f(x)在 (-infty ,+infty ) 内连续,则 (int )_(2)^3f(x)dx+(int )_(3)^2f(t)dt+(i