问答题设(X，Y)的联合概率密度为求：

问答题设(2E-C-1B)=AT=C-1，其中E是4阶单位矩阵，AT是4阶矩阵A的转置矩阵，求A．

问答题设函数f(x)在a≤x≤b上有定义，并且连续，可微．证明：在a＜x＜b上有，其中ξ是a与b之间的某数．

问答题已知向量组有相同的秩，且β3可由α1，α2，α3线性表出，求a，b的值．

问答题已知在(-∞，+∞)上存在原函数，求常数A并求f(x)的原函数。

问答题设，

问答题设f(x)=3x 2 +Ax -3 (x＞0)，A为正常数，问A至少为多少时，f(x)≥20?

问答题设区域D=(x，y)|x2+y2≤1，x≥0，计算二重积分。

问答题71.Vacations were once the prerogative of the privileged few, even as late as the 19th century. Now they are considered the right of all, except for such unfotrunate masses as, for example, the bulk of puplation in certain countries, for whom life, save for sleep and brief periods of rest, is uniterrupted toil. Vacations are more necessary now than before because today the average life is less well-rounded and has become increasingly compartmentalized. 72. I suppose the idea of vacations, as we conceive it, must be incomprehensible to primitive peoples. Rest of some kind has of course always been a part of the rhythm of human life, but earlier ages did not find it necessary to organize it in the way that modern man has done. Holidays and feast days were sufficient. With modern man's increasing tensions, with the stultifying quality of so much of his work, this break in the year's routine became steadily more necessary. 73. Vacations became mandatory for the purpose of renewal and repair. And so it came about that in the United States, the most self-indulgent of nations, the most tense and compartmentalized, vacations have come to take a predominant place in domestic conversation.

问答题求幂级数的收敛区间及和函数，并求级数的和．

问答题若σ有n,个不同特征值，则σ可对角化. 若σ可对角化，则σ有n个不同特征值？

问答题设A，B满足A*BA=2BA-8E，且，求B．

问答题设f(x)在(-∞，+∞)上具有二阶导数，且满足条件|f(x)|≤a，|f"(x)|≤b，其中a，b是两个正的常数，求证：有

问答题设f(x)在[0，2]上连续，在(0，2)内三阶可导，且证明：存在ζ∈(0，2)，使得

问答题求由方程siny+xey=0确定的曲线在点(0，π)处的切线方程．

问答题求y"-2y'+y=0的通解．

问答题设4x 2 +4y 2 +3z 2 =32，证明2xy+3yz≤16．

问答题设起点站上车人数X服从参数为λ(λ＞0)的泊松分布，每位乘客中途下车的概率为p(0＜p＜1)，且中途下车与否相互独立，以Y表示中途下车人数．

问答题求由y=x2与所围成的封闭平面图形的面积，并求该平面图形绕x轴旋转一周所生成的旋转体体积V。