搜题请搜索小程序“爱下问搜题”
问题 填空题

点P（x，y）在直线x+y-4=0上，则x2+y2的最小值是______．

答案

原点到直线x+y-4=0的距离

4
2
．

点P（x，y）在直线x+y-4=0上，则x2+y2的最小值，

就是求原点到直线的距离的平方，为：(

4
2
)2=8

故答案为：8

填空题

During the 1980s, unemployment (失业人数) and underemployment (不充分就业) in some countries was so high as 90 per cent. Some countries did not 【B1】 enough food; basic needs in housing and clothing were not 【B2】 . Many of these countries looked 【B3】 the industrial processes of the developed nations for solution. 【B4】 , problems cannot always be solved by 【B5】 the industrialized nations. Industry in the developed nations is highly automated and very 【B6】 . It provides fewer jobs than labor-intensive industrial 【B7】 , and highly skilled workers are needed to 【B8】 and repair the equipment. These workers must be trained, 【B9】 many nations do not have the necessary training institutions. Thus, the 【B10】 of importing industry becomes higher. Students must be sent abroad to receive vocational and 【B11】 training. 【B12】 , just to begin training, the students must 【B13】 learn English, French, Germans, or Japanese. The students then spend many years abroad, and 【B14】 do not return home. All nations agree that science and technology should be shared. The point is: countries 【B15】 the industrial processes of the developed nations need to look carefully 【B16】 the costs, be cause ninny of these costs are 【B17】 Students from these nations should 【B18】 the problems of the industrialized countries closely. 【B19】 care, they will take home not the problems of science and technology, 【B20】 the benefits.

A．Frequently

B．Gradually

C．Presumably

D．Eventually
查看答案
单项选择题

女性，67岁，双膝关节痛、畸形5年，现只能忍痛行走100米。检查：O形腿，膝关节活动范周30～ 60°，X线平片示双膝内侧关节间隙消失，股胫角 190°治疗首选

A．卧床休息，保护患肢

B．关节镜下膝关节清洗

C．关节内注射局麻药及类固醇激素

D．人工全膝关节置换

E．膝关节融合术
查看答案