某人向同一目标独立重复射击，每次射击命中目标的概率为p(0＜p＜1)，则此人第4次射击恰好第2次命中目标的概率为()A. 3p(1-p)2 ।B. 6p(1-p)2 ।C. 3p 2 (1-p)2 ।D. 6p 2 (1-p)2 ।

设_(1),(X)_(2),... (X)_(n)... .是独立同分布的随机变量序列，且具有相同数学期望和方差，_(1),(X)_(2),... (X)_(n)... .,则对于任意实数_(1),(X)_(2),... (X)_(n)... . , _(1),(X)_(2),... (X)_(n)... ._(1),(X)_(2),... (X)_(n)... ._(1),(X)_(2),... (X)_(n)... ._(1),(X)_(2),... (X)_(n)... ._(1),(X)_(2),... (X)_(n)... .

8.求齐次线性方程组-|||- ) 2(x)_(1)+(x)_(2)-(x)_(3)+(x)_(4)-3(x)_(5)=0 (x)_(1)+(x)_(2)-(x)_(3)+(x)_(5)=0 .-|||-的解空间(作为R ^5的子空间)的一组标准正交基.

在下列各题中,确定函数关系式中所含的参数,使函数满足所给的初值-|||-条件:-|||-(1) ^2-(y)^2=C |x=0=5;-|||-(2) =((C)_(1)+(C)_(2)x)(e)^2x, |x=0=0,y'|=0=1;-|||-(3) =(C)_(1)sin (x-(C)_(2)) |x=pi =1, '|x=pi =0.

设 _(1)=(a)_(1)+(a)_(2) , _(2)=(a)_(2)+(a)_(3),-|||-_(3)=(a)_(3)+(a)_(4) , _(4)=(a)_(4)+(a)_(1), 证明向量组-|||-b1, b2,b3,b4线性相关.

21.设3阶矩阵A的特征值为 (lambda )_(1)=2, (lambda )_(2)=-2 (lambda )_(3)=1, 对应的特征向量依次为-|||-(0 1) (1)-|||-p1= 1 p2= 1 p3= 1-|||-1) 1 0

曲线 x=t-sin t, y=-cos t, z=4sin (t)/(2) 在 t=(pi)/(2) 处切线的方向向量为() A. overrightarrow(T)=(1,sqrt(2),1)B. overrightarrow(T)=(sqrt(2),1,1)C. overrightarrow(T)=(sqrt(2),sqrt(2),1)D. overrightarrow(T)=(1,1,sqrt(2))

2.画出积分区域,并计算下列二重积分:-|||-(1) iint xsqrt (y)dsigma , 其中D是由两条抛物线 =sqrt (x) =(x)^2 所围成的闭区域;-|||-(2)厂xy^2dσ,其中D是由圆周 ^2+(y)^2=4 及y轴所围成的右半闭区域;-|||-(3) iint (e)^x+ydsigma , 其中 = (x,y)||x|+|y|leqslant 1 ;-|||-(4) iint ((x)^2+(y)^2-x)do, 其中D是由直线 y=2 =x 及 y=2x 所围成的闭区域.

[题目]设有直线L: ) x+3y+2z+1=0 2x-y-10z+3=0 . 及平面-|||-pi :4x-2y+z-2=0, 则直线L() ()-|||-A.平行于π-|||-B.在π上-|||-C.垂直于π-|||-D.与π斜交

1.求下列微分方程的通解:-|||-(1) '-yln y=0;-|||-(2) (x)^2+5x-5y'=0;-|||-(3) sqrt (1-{x)^2}y'=sqrt (1-{y)^2};-|||-(4) '-xy'=a((y)^2+y');-|||-(5) (sec )^2xtan ydx+(sec )^2ytan xdy=0;-|||-(6) dfrac (dy)(dx)=(10)^x+y;-|||-(7) ((e)^x+y-(e)^x)dx+((e)^x+y+(e)^y)dy=0;-|||-(8) cos xsin ydx+sin xcos ydy=0;-|||-(9) ((y+1))^2dfrac (dy)(dx)+(x)^3=0;-|||-(10) +((x)^2-4x)dy=0.

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