ow to moul u-|||-心的影鲁L......-|||-剩余:00:31:58 2/50 ①-|||-2(2分 :"-|||-概率的取值范围是p() ()-|||-A 小于1-|||-一__ -|||-__-|||-B 在0与1之间-|||-一-|||-C 大于1-|||-__ __-|||-__-|||-D 大于 -1 __

形状为椭球 (x)^2+(y)^2+4(z)^2leqslant 16 的空间探测器进入地球大气层,其表面开始受-|||-热,1小时后在探测器的点(x,y,z)处的温度 =8(x)^2+4yz-16z+600, 求探测器表面-|||-最热的点.

设Sigma为抛物面z=(x^2+y^2)/(2)(0leq zleq 2)，取下侧，则曲面积分iint_(Sigma)4zxdydz-2zdzdx+(1-z^2)dxdy=(）. A. (68)/(3)piB. (32)/(3)piC. 12piD. -12pi

设 L 是由原点 O 沿 y=x^2 到点 A(1,1)，再由点 A 沿直线 y=x 到原点的闭曲线，则 int_(L) arctan (y)/(x) , dy - dx = ( )。 A. (pi)/(2) - 1B. 1 - (pi)/(4)C. (pi)/(4) - 1D. (pi)/(2) - 2

15.求下列函数的极值.-|||-(1) (x,y)=(x)^3-4(x)^2+2xy-(y)^2+3 ;-|||-(2) (x,y)=3xy-(x)^3-(y)^3 ;-|||-(3)f (x,y)=(e)^2x(x+(y)^2+2y) ;-|||-(4) (x,y)=(6x-(x)^2)(4y-(y)^2) ;-|||-(5) (x,y)=4(x-y)-(x)^2-(y)^2 ,-|||-(6) (x,y)=xy+dfrac (8)(x)+dfrac (27)(y) .-|||-(7) (x,y)=(e)^x-y((x)^2-2(y)^2 );-|||-(8) (x,y)=(x)^3+(y)^3-3((x)^2+(y)^2) .

设矩阵满足则_______________ .

谢谢您！设∑为平面 x+y+z=1 被三个坐标面所截部分,则曲面积分-|||-(iint )_(2)^1dfrac (1)({(1+x+y))^2}dS= () .-|||-A. sqrt (3)-|||-B. sqrt (3)(ln 2-1)-|||-C. sqrt (3)(ln 2-dfrac (1)(2))-|||-D. sqrt (3)ln 2

求指导本题解题过程，谢谢您！13、判断 若正项级数 _(n)gt 0, 则必-|||-un-|||-n=1-|||-有 lim _(narrow infty )dfrac ({u)_(n+1)}({u)_(n)}=rho , 且 lt 1 ()-|||-A-|||-B x-|||-(3分)

已知非齐次线性方程组 |} (x)_(1)+(x)_(2)+(x)_(3)+(x)_(4)=-1 4(x)_(1)+3(x)_(2)+5(x)_(3)-(x)_(4)=-1 a(x)_(1)+(x)_(2)+3(x)_(3) .，有3个线性无关的解，证明:(1)方程组系数矩阵A的秩 |} (x)_(1)+(x)_(2)+(x)_(3)+(x)_(4)=-1 4(x)_(1)+3(x)_(2)+5(x)_(3)-(x)_(4)=-1 a(x)_(1)+(x)_(2)+3(x)_(3) .;(2)当 |} (x)_(1)+(x)_(2)+(x)_(3)+(x)_(4)=-1 4(x)_(1)+3(x)_(2)+5(x)_(3)-(x)_(4)=-1 a(x)_(1)+(x)_(2)+3(x)_(3) .时， |} (x)_(1)+(x)_(2)+(x)_(3)+(x)_(4)=-1 4(x)_(1)+3(x)_(2)+5(x)_(3)-(x)_(4)=-1 a(x)_(1)+(x)_(2)+3(x)_(3) ..

设随机变量（X，Y）的概率密度为 f(x,y)= ) k, 0lt xlt 1,0lt ylt x, 0, .-|||-. 试确定常数k，并求E（XY）.

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