问答题设常数a＞，函数f(x)=ex-ax2，证明方程f(x)=0在区间(0，+∞)内有且仅有两个实根．

问答题设f(x)在[a，b]上连续，在(a，6)内可导，且f(a)=a，f(b)=b，试证在(a，b)内存在ξi(i=1，2，…，n)，使

问答题已知两直线求过L1且平行于L2的平面的方程．

问答题设矩阵．当a为何值时，方程AX=B无解、有唯一解、有无穷多解?在有解时，求此方程．

问答题计算，其中D={(x，y)|x2+y2≥1，x+y≤2，x-y≥-2，y≥0}．

问答题。

问答题如图13-2，设单位圆x2+y2=1上点M(x0，y0)处的切线L与抛物线y=x2-2围成的图形的面积S达到最小，求点M的坐标和切线L的方程．

问答题将展开成x的幂级数，并指明其成立范围，并求级数的和．

问答题{{I}}Directions: Read the following text carefully and then translate the underlined segments into Chinese. Write your pieces of Chinese version in the proper space on your Answer Sheet Ⅱ.{{/I}} As we enter the 21st century, the gap between the world's rich and poor is widening, both with in and among countries. 1. {{U}}The vast majority of the world's population is receiving an ever-decreasing share of its collective wealth, while the share claimed by a few rich nations and individuals is steadily growing.{{/U}} In 2001 Forbes magazine counted 538 billionaires with a total net worth of 1.7 trillion dollars, while the United Nations identified 2.8 billion people surviving on less than two dollars a day. Overall, the richest 20 percent of the world's people control 86 percent of global income, while the poorest 20 percent control barely one percent. The impacts of this widening rich-poor gap are varied and worrisome. 2. {{U}}They include environmental destruction—richer nations and individuals can afford to over-consume resources, poorer nations and individuals are forced to over-exploit the environment just to survive.{{/U}} They include migration—people are forced to, move in search of adequate resources. And they include conflict—wealthier nations and individuals fight to keep what they have, while those suffering a lack of resources fight to obtain them. 3. {{U}}Because poorer groups typically lack the assets and technology to conduct large-scale conventional war to obtain their goals, they often resort to low-intensity conflict and terrorism.{{/U}} The causes of this global disparity are diverse and complex, but include colonial era trading patterns that favor industrialized nations; the globalization of economies and economic structures, in which poor nations struggle to compete; a growing "digital divide" characterized by lack of access to information technology; inadequate governance and protection of law; and lack of access to education, healthcare, and social safety nets, especially for women and girls. 4. {{U}}Individuals and nations need not remain in poverty indefinitely, however.{{/U}} With an awareness of the interdependence of our modern world and a concerted political will, it is possible to reverse this trend that threatens to divide the world against itself. And reversing this trend would have powerful and positive impacts on our future. 5. {{U}}Bringing the nearly 5 billion people of the less industrialized world into a sustainable economy through "pro-poor" policies would provide a tremendous boost to the world economy, as well as to those people.{{/U}} With increased economic opportunities come improved access to nutrition, education, and health care. With those come higher income, greater autonomy—especially for women—and the opportunity to pursue environmentally sound technologies and products.

问答题求。

问答题计算．

问答题求极限

问答题讨论函数的连续性．