题目

在空间直角坐标系中,以点A(4,1,9)、B(10,-1,6)、C(x,4,3)为顶点的△ABC是以BC为斜边的等腰直角三角形,则实数x的值为 .  答案：2解析:=(6,-2,-3), =(x-4,3,-6), 由题意知·=0, ||=||,6(x-4)-6+18=0. 可解得x=2.We often use the words growth and development as if they meant essentially the same thing. But this may not always be the case. One can easily imagine instances in which a country has achieved higher levels of income (growth) with little or no benefit coming to most of its citizens (development).In the past, most development policies were aimed increasing the growth rate of income per capita. Many still are, based on the theory that benefits of economic growth will come to all members of society. If this theory is correct, growth should promote development.By the early 1970s, however, the relationship between growth and development was being questioned. A major study by the World Bank in 1974 concluded that it is now clear that more than a decade of rapid growth in underdeveloped countries has been of little benefit to a third of their population.The World Bank study indicated that increases in GNP per capita did not promise important improvements in such development indicators as nutrition, health, and education. Although GNP per capita did indeed rise, its benefits come down to only a small part of the population. This realization gave rise to a call for new development policies. These new policies favored agriculture over industry, called for domestic redistribution of income and wealth, and encouraged programs to satisfy such basic needs as food and shelter.In the late 1970s and early 1980s, the international macroeconomic crises of high oil prices, worldwide recession, and third world debt forced attention away from programs designed to get rid of poverty. However, the lesson remains: economic growth does not promise economic development. Efforts may be required to change growing output capacity into economic benefits that reach most of a nation’s people. 小题1:As to the relationship between growth and development, what can we infer from the passage?A．Development is a reliable measure of growth.B．Growth always brings about development.C．Development is not necessarily the result of growth.D．Growth and development refer to the same thing.小题2:According to the study by the World Bank in 1974,economic growth in some background countries brought A．benefit only to a third of their population.B．almost no benefit to a third of their population.C．little benefit to their people.D．no benefit at all to their people.小题3:The programs designed to get rid of poverty were not very well carried out because the governmentA．knew that growth didn’t promise development.B．gave too much attention to increases in GNP per capita.C．wished to replace the programs with new development policies.D．was busy solving other more serious economic problems.小题4:If the passage continues, what is the author most likely to discuss in the next paragraph?A．How to turn growth into development.B．How to remove poverty from society.C．How to decrease third world debt.D．How to cope with economic crises.