7.已知-1 -2)=1/3 (-1 -4)( -1 0-|||-2-|||-1 4-|||-且-|||--1 -1-|||-dfrac (1)(3) -1 -4 1 .-1 =-|||-1 0-|||-1 1八 -1 0 1-|||-3 4 11-|||-计算 -1 -2

7.设事件A与B互不相容, (A)=0.4, (B)=0.3, 求P(AB)与 (overline (Acup B)).

14.(1)已知 (overline (A))=0.3 (B)=0.4, (Aoverline (B))=0.5, 求条件概率 (B|Acup overline (B)).-|||-(2)已知 (A)=1/4, (B|A)=1/3, (A|B)=1|2, 求P(AUB).

地球的直径约是1.28万千米，月球到地球的距离约是地球直径的30倍，那么月球到地球有多远？

[题目]甲乙两人相约上午8点到9点在某地会面,-|||-先到者等候另一人20分钟,过时离去,求甲乙两人-|||-能会面的概率.

从5双不同的鞋子中任取4只，问这4只鞋子中至少有两只配成一双的概率是多少？

(16)设 D= |} 1& 2& 3& 4 2& 3& 4& 1 3& 4& 1& 2 4& 1& 2& 3= __ ;

(16)已知A,B均为3阶矩阵，|A|=0,且满足AB+3B=O,若r(B)=2,则行列式|A+2E|=____.

求下面图形的面积。(单位：cm)3.2 square -|||-6.25-|||-square 4.5-|||-4.5-|||-4.23-|||-4.5 square 5.9

14.确定下列函数极限是否存在,若存在则求出极限:-|||-(1) lim _(xarrow (x))(dfrac (x)(x)) 其中 = (x,y):ygt {x)^2} ;-|||-(2) lim _((x,y)arrow (0,0))xln ((x)^2+(y)^2);-|||-(3) lim _((x,y)|arrow +infty )((x)^2+(y)^2)(e)^-(|x|+|y|);-|||-(4) |lim _(xarrow 0)||-dfrac ({x)^2}(|x|+|y|)-|||-(5) lim _((x,y)zxarrow (0,0,0))((dfrac {xyz)({x)^2+(y)^2+(z)^2})}^x+y-|||-(6) Longrightarrow (x,y,z)arrow (0,0,0) (x)^yz, 其中 = (x,y,z):x,y,zgt 0 ;-|||-(7) (x,y,z)arrow (0,1,0)dfrac (sin (xyz))({x)^2+(z)^2};-|||-(8) lim _((x,y,z)arrow (0,0,0))dfrac (sin xyz)(sqrt {{x)^2+(y)^2+(z)^2}}-|||-(9) lim _(xarrow 0)dfrac ({(sum _{i=1)^n(x)_(i))}^2}({|x|)^2}

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