6、设(X,Y)的分布律为 X-|||-Y 0 2-|||-0 k dfrac (5)(33)-|||-1 dfrac (5)(33) dfrac (1)(66
10.气相总阻力可表示为 dfrac (1)({K)_(6)}=dfrac (1)({K)_(6)}+dfrac (1)(H{K)_(1)}, 其中 dfrac
X=k =dfrac (c)(k!) ,=0, 1,2,3...... X=k =dfrac (c)(k!) ,=0, 1,2,3...... X=k =dfr
7.设 (x,y)=dfrac (1)(xy),r=sqrt ({x)^2+(y)^2} _(1)= (x,y)|(x,y)in {R)^2 dfrac (1)
)-|||-B .(X=k)=dfrac (1)({3)^k}(k=1,2,... )-|||-C .(X=k)=dfrac (1)({3)^k}(k=0,1
).,求:(1)参数a; X=k =dfrac (a)({2)^k}(k=1,2,... ).; X=k =dfrac (a)({2)^k}(k=1,2,...
直线dfrac (x-1)(1)=dfrac (y)(2)=dfrac (z+3)(-2)-|||-__ __-|||-__与平面dfrac (x-1)(1)=
求直线dfrac (x-1)(1)=dfrac (y)(1)=dfrac (z-1)(-1)-|||-__ __在平面dfrac (x-1)(1)=dfrac
直线dfrac (x-1)(1)=dfrac (y-1)(0)=dfrac (z-1)(-1)-|||-__与直线dfrac (x-1)(1)=dfrac (y
29.设随机变量(X Y)的分布律为-|||-x .-1 0 1-|||-Y-|||--1 dfrac (1)(8) .dfrac (1)(8) dfrac (