单选题下列极限中正确的是（ ）

单选题已知α=(1，3，2)T，β=(1，-1，-2)T，又A=E-αβT，k是非0常数，则矩阵A的最大特征值所对应的特征向量是

单选题过点(1，0)作曲线y=x2的两条切线，它们与曲线y=x2所围图形的面积是( )．

单选题交错级数的和S=A．．B．．C．．D．．

单选题After the terrorist attacks in America last September, terrorist risk became the pariah of perils. The airline industry was most directly affected by the attacks, and it was the first to find that no one wanted to insure terrorist risk. Insurance companies immediately increased premiums and cut cover for airlines' third-party terror and war liabilities to $ 50m per airline, per "event". Under pressure from airlines, the American government and the members of the European Union agreed to become insurers of last resort for airlines' war and terrorist liabilities, for a limited period. These government guarantees are due to expire at the end of the month. The American government has already agreed to extend its guarantee for another 60 days. The EU's transport ministers are meeting next week in Brussels to decide what to do. Insurers and reinsurers are keen for the commercial market to resume the provision of all airline insurance as soon as possible. No wonder: The premiums for such cover have inevitably increased considerably. However, in the case of terrorism, and especially of terrorism in the skies, a number of special factors arise. Some are purely practical: a disaster as sudden and unforeseen as the attacks on the World Trade Center has had destructive effects on the insurance industry. The maximum cover for third-party terrorist risk available in the primary aviation market is now $ 50m, and that is not nearly enough cover risks that are perceived to be much higher since September 11th. Even if the market could offer sufficient cover, another catastrophe on such a scale would be more than the market could cope with. In addition, a rare and devastating risk of a political nature is arguably one that it is right for governments to cover, at least in part. In the wake of attacks by Irish terrorists the British government has recognized this point by agreeing to back a mutual fund to cover risks to property from terrorist attack. In the case of the airlines, the appropriate answer is some form of mutual scheme with government backing. In fact, under the code-name "Equitime", representatives of airlines, insurers and the American government are setting up an insurance vehicle to be financed by airlines and reinsured by the government. Governments would guarantee the fund's excess. risk, but their role would diminish as the fund grew. Setting something up will take time. So, to bridge the gap, governments will have to remain insurer of last resort for airlines' war and terrorist risk for some time to come.

单选题设f(x)在x=a处可导，且f(a)≠0，则|f(x)|在x=a处______．

单选题已知函数y=f(x)的图像与函数y=2x+1的图像关于直线x=2对称，则f(x)=______。

单选题函数y=cos3(5x+2)的复合过程是______ A.y=cos3u，u=5x+2 B.y=u3，u=cos(5x+2) C.y=u3，u=cosv，v=5x+2 D.y=cosu3，u=5x+2

单选题设y 1 ，y 2 为二阶线性常系数微分方程y"+p 1 y’+p 2 y=0的两个特解，则C 1 y 1 +C 2 y 2 ( )

单选题设f(x)=arctanx，则

单选题当x→0时，无穷小的阶数最高的是______．A．B．tanx-xC．(1+tanx)ln(1+2x)-1D．

单选题已知f(x)=3x+e x ，则f"(0)等于

单选题已知直线l1：(a+2)x+(1-a)y-3=0和直线l2：(a-1)x+(2a+3)y+2=0互相垂直，则a等于______．A．-1B．1C．±1D．E．0

单选题满足的x的集合是()．

单选题两个正数a与b 使得, a, b, a+b成等比数列，则其公比是（ ）

单选题若f(x)在x=0的某邻域内二阶连续可导，且，则下列正确的是______．

单选题解决社会主义初级阶段主要矛盾的根本手段是______。 A．进行阶级斗争 B．发展生产力 C．进行社会主义改造 D．提倡低消费

单选题设α是实数，f(x)在x=1处可导，则α的取值为