单选题设A为n(n≥2)阶方阵，A*为A的伴随矩阵，若对任一n维列向量α，均有A*α=0，则齐次线性方程组Ax=0的基础解系所含解向量的个数k必定满足______

单选题设A，B是n阶矩阵，则下列结论正确的是______A．B．C．D．

单选题______A．B．C．D．

单选题Many countries have a tradition of inviting foreigners to rule them. The English called in William of Orange in 1688, and, depending on your interpretation of history, William of Normandy in 1066. Both did rather a good job. Returning the compliment, Albania asked a well-bred Englishman called Aubgrey Herbert to be their king in the 1920s. He refused-and they ended up with several coves called Zog. America, the country of immigrants, has no truck with imported foreign talent. Article two of the constitution says that "no person except a natural-born citizen.., shall be eligible to the office of the president". This is now being challenged by a particularly irresistible immigrant: Arnold Schwarzenegger. Barely a year has passed since the erstwhile cyborg swept to victory in California's recall election, yet there is already an Amend-for-Arnold campaign collecting signatures to let the Austrian-born governor have a go at the White House. George Bush senior has weighed in on his behalf. There are several "Arnold amendments" in Congress. one allows foreigners who have been naturalized citizens for 20 years to become president. (The Austrian became American in 1983.) It is easy to dismiss the hoopla as another regrettable example of loopy celebrity politics. Mr. Schwarzenegger has made a decent start as governor, but he has done little, as yet, to change the structure of his dysfunctional state. Indeed, even if the law were changed, he could well be elbowed aside by another incomer, this time from Canada. the Democratic governor of Michigan, Jennifer Granholm, who appears to have fewer skeletons in her closet than the hedonistic actor. Moreover, changing the American constitution is no doddle. It has happened only 17 times since 1791 (when the first ten amendments were codified as the bill of rights). To change the constitution, an amendment has to be approved by two-thirds of both houses of Congress, and then to be ratified by three-quarters of the 50 states. The Arnold amendment is hardly in the same category as abolishing slavery or giving women the vote. And, as some wags point out, Austrian imports have a pretty dodgy record of running military superpowers.

单选题设，则M1，M2，M3，M4中不能与对角矩阵相似的是______

单选题设A是m×n矩阵，且方程组Ax=β有解，则

单选题设A，B都是n阶矩阵，且存在可逆矩阵P，使得AP=B，则______．

单选题设A，B为n阶矩阵，A*，B*分别为A，B对应的伴随矩阵，分块矩阵，则C的伴随矩阵C*=

单选题某产品的产量Q与原材料A，B，C的数量x，y，z(单位均为吨)满足Q=0.05xyz，已知A，B，C的价格分别是3，2，4(百元)．若用5400元购买A，B，C三种原材料，则使产量最大的A，B，C的采购量分别为： A.6，9，4．5(吨)． B.2，4，8(吨)． C.2，3，6(吨)． D.2，2，2(吨)．

单选题若，其中a＞0为常数，则区域D是A.{(x，y)|x2+y2≤a2}．B.{(x，y)|x2+y2≤ax}．C.{(x，y)|x2+y2≤a2，x≥0}．D.{(x．y)|x2+y2≤ay}．

单选题设F(t)=，则F"(1)=______