PresentatthehistoricmeetingmanyanofficialonNov7，ofcoursePresidentXiJinpingandMaYing-jeou．（）A.was；includedB.was；includingC.were；includedD.hasbeen；included
Present at the historic meeting ______ many an official on Nov 7，of course President Xi Jinping and Ma Ying-jeou _______．（ ）
A. was； included
B. was； including
C. were； included
D. has been； included
设A是n阶矩阵A^2=E,证明r(A+E)+r(A-E)=n,的一步证明过程不懂由A^2=E,得A 2020-05-14 …
已知a+b+c=H a+b+e=J a+d+e=K b+c+d=M c+d+e=N 求a=?b=? 2020-05-16 …
设a>0,f(x)=e^x/a+a/e^x是R上的偶函数,求a值.∵f(x)=e^x/a+a/e^ 2020-05-17 …
a+b+c+d+e=abcde,a,b,c,d,e均是正整数,求e的最大值由于a，e在式中对称，故 2020-06-09 …
协方差cov(X+20,Y+10)=cov(X,知道了COV(X+a,Y+b)=E[(X+a)(Y 2020-06-17 …
矩阵平方差设方阵A满足A²-A-2E=O,求A的逆矩阵.答案是1/2（A-E）.为啥不是1/2E, 2020-07-18 …
已知函数y=(e^x-a)^2+(e^(-x)-a)^2(a属于R,a不等于0),求y的最小值Y= 2020-07-21 …
已知向量a≠e,|e|=1,满足:任意t∈R.已知向量a不等于e,|e|=1,对任意t属于R,恒有 2020-07-25 …
若函数f(x)在R上可导,且f(x)＞f'(x),当a>b时,下列不等式成立的是A.e^af(若函 2020-07-29 …
已知向量a≠e,|e|=1,对任意t∈R,恒有|a-te|≥|a-e|,则（a,e皆为向量）A.a⊥ 2020-11-02 …