设(X,Y)的分布函数为(x,y)=dfrac (1)({pi )^2}(dfrac (pi )(2)+arctan dfrac (x)(2))(dfrac (pi )(2)+arctan y)，求：(1)边缘分布函数(x,y)=dfrac (1)({pi )^2}(dfrac (pi )(2)+arctan dfrac (x)(2))(dfrac (pi )(2)+arctan y);(2)判断X与Y是否独立；(3)(x,y)=dfrac (1)({pi )^2}(dfrac (pi )(2)+arctan dfrac (x)(2))(dfrac (pi )(2)+arctan y).

1.设随机向量(X,Y)的分布函数在 leqslant xleqslant dfrac (pi )(2) leqslant yleqslant dfrac (p

(9) (int )_(-dfrac {pi )(2)}^dfrac (pi {2)}|sin x|arctan (e)^xdx

6.求下列各函数的函数值:-|||-(1) (x,y)=([ dfrac {arctan (x+y))(arctan (x-y))] }^2 ,求 (dfrac

(2) lim _(xarrow +infty )((dfrac {2)(pi )arctan x)}^x;

设(x)=((2-x))^tan dfrac (pi {2)x},(dfrac (1)(2)lt xlt 1),求(x)=((2-x))^tan dfrac (

求lim _(xarrow +infty )((dfrac {2)(pi )arctan x)}^x-|||-__求

3、设 (x,y)=arctan dfrac (x)(y), 则 (1,1)=-|||-(A)1; (B)0; (C) dfrac {1)(2),dfrac

设=(int )_(-dfrac {pi )(2)}^dfrac (pi {2)}dfrac (sin x)(1+{x)^2}(cos )^4xdx, =(in

2.求微分方程 =dfrac (y)(x)+tan dfrac (y)(x), 满足 |,x|=dfrac (pi )(6) 的特解.

1.设 sin y+(e)^x-x(y)^2=0, 求 dfrac (dy)(dx).-|||-2.设 ln sqrt ({x)^2+(y)^2}=arctan