单选题设，则A-1=A．B．C．D．

单选题假设甲、乙两国关于拥有洲际导弹数量的关系曲线y=f(x)和x=g(y)的意义是： 当甲国拥有导弹x枚时，乙国至少需储备导弹y=f(x)枚，才有安全感； 当乙国拥有导弹y枚时，甲国至少需储备导弹x=g(y)枚，才有安全感． 这两条曲线将坐标平面的第一象限分成四个 区域Ⅰ，Ⅱ，Ⅲ，Ⅳ，如图图5-1所示．双方均有安全感的区域是( )．

单选题设f(x，y)在点P 0 (x 0 ，y 0 )的某邻域内有连续的二阶偏导数

单选题把浓度为50%的酒精溶液90千克全部稀释为浓度为30%的酒精溶液，需要加水______千克。 A．60 B．70 C．85 D．105

单选题设A，B为实对称矩阵，则A合同于B，如果

单选题设为______．A．B．C．D．

单选题()A．绝对收敛B．条件收敛C．发散D.收敛性与口有关

单选题下列说法中错误的是______(设D(X)≠0，D(Y)≠0)．

单选题如下图所示，AB∥CD，若∠ABE=120°，∠DCE=35°，则∠BEC=______

单选题设函数f(x)在x=x 0 处存在三阶导数，且f"(x 0 )=0，f"(x 0 )=0，f"""(x 0 )=a＞0，则

单选题Twenty-seven years ago, Egypt revised its secular constitution to enshrine Muslim sharia as "the principal source of legislation". To most citizens, most of the time, that seeming contradiction-between secularism and religion-has not made much difference. Nine in ten Egyptians are Sunni Muslims and expect Islam to govern such things as marriage, divorce and inheritance. Nearly all the rest profess Christianity or Judaism, faiths recognised and protected in Islam. But to the small minority who embrace other faiths, or who have tried to leave Islam, it has, until lately, made an increasingly troubling difference. Members of Egypt's 2,000-strong Bahai community, for instance, have found they cannot state their religion on the national identity cards that all Egyptians are obliged to produce to secure such things as driver's licenses, bank accounts, social insurance and state schooling. Hundreds of Coptic Christians who have converted to Islam, often to escape the Orthodox sect's ban on divorce, find they cannot revert to their original faith. In some cases, children raised as Christians have discovered that, because a divorced parent converted to Islam, they too have become officially Muslim, and cannot claim otherwise. Such restrictions on religious freedom are not directly a product of sharia, say human- rights campaigners, but rather of rigid interpretations of Islamic law by over-zealous officials. In their strict view, Bahai belief cannot be recognised as a legitimate faith, since it arose in the 19th century, long after Islam staked its claim to be the final revelation in a chain of prophecies beginning with Adam. Likewise, they brand any attempt to leave Islam, whatever the circumstances, as a form of apostasy, punishable by death. But such views have lately been challenged. Last year Ali Gomaa, the Grand Mufti, who is the government's highest religious adviser, declared that nowhere in Islam's sacred texts did it say that apostasy need be punished in the present rather than by God in the afterlife. In the past month, Egyptian courts have issued two rulings that, while restricted in scope, should ease some bothersome strictures. Bahais may now leave the space for religion on their identity cards blank. Twelve former Christians won a lawsuit and may now return to their original faith, on condition that their identity documents note their previous adherence to Islam. Small steps, perhaps, but they point the way towards freedom of choice and citizenship based on equal rights rather than membership of a privileged religion.

单选题设f"(x)在x=0处连续，且则

单选题一个正偶数的算术平方根是口，那么与这个正偶数相邻的下一个正偶数的算术平方根是( )。

单选题设，则f(x，y)等于______A．B．C．D．