设复数_(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)，且_(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)，则（ ）。A _(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)B _(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)C _(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)且_(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)D _(1)=(x)_(1)+i(y)_(1), _(2)=(x)_(2)+i(y)_(2)

[题目]-|||-_(1)=iint ((x+y))^3dxdy,(I)_(2)=iint ((x+y))^2dxdy, 其中 :((x-2))^2+((y-1

若 Y=X_(1)+X_(2)，X_(i) sim N(0,1)，i=1,2，则（）A. $E(Y)=0$；B. $D(Y)=2$；C. $Y \sim N(0

已知调和函数 (x:y)=2(x)^2-2(y)^2+x ,求函数v(x,y),-|||-使函数 (z)=u(x,y)+i(x,y) 解析且满足 f(-1)=1

3.设X_(1),...,X_(10)为来自标准正态总体Xsim N(0,1)，Y_(1)=7sum_(i=1)^3X_(i)^2,Y_(2)=3sum_(i=

10.设f(x,y)=}x-y+1,x+yleqslant1, (1)/(sqrt(x^2)+y^(2)),x+y>1,.计算I=iintlimits_(D)f

22.(1)设随机变量X 1,X2,X3,X4相互独立,且有 ((X)_(i))=i ,((X)_(i))=5-i i=1 ,2,3,4.设 Y=-|||-.(

微分方程x^2y`+xy= y^2, y|x=1=1 的特解为A x^2y`+xy= y^2, y|x=1=1 B x^2y`+xy= y^2, y|x=1=1

设X_1, X_2, ldots, X_n是来自总体N(mu, sigma^2)的样本，令Y = (sum_(i=1)^n(X_i - overline(X))

设D是由x轴、y轴与直线 x + y = 1所围成,比较 I_(1) = iint limits _(D) (x + y)^2, d delta , I_(

22 （1）设随机变量X_(1),X_(2),X_(3),X_(4)相互独立，且有E(X_(i))=i,D(X_(i))=5-i,i=1,2,3,4.设Y=2X