搜题请搜索小程序“爱下问搜题”
问题 填空题

已知x+y=2，则2x+2y的最小值为______．

答案

∵2x+2y≥2

2x×2y
=2
2x+y
=2
22
=4．当且仅当2x=2y，x+y=2，即x=y=1时取等号．

因此2x+2y的最小值为4．

故答案为4．

完形填空

People around the world may feel that the climate _小题1:__ (get) steadily warmer and warmer in recent years. Places _小题2:_ used to be abundant in snowfall have frequently experienced snow-free (无雪的) winters. Droughts last _小题3:_(long) in some dry areas. People find that _小题4:_ air conditioners they could hardly work or fall asleep in hot summer days.

The side effects of global warming are alarming. __小题5:_ warming global climate melts the ice caps，_小题6:_ (raise) sea levels. What is more，_小题7:_ disturbs weather patterns, causing droughts, severe storms and hurricanes. People suffer a lot from disasters relevant to global warming. __小题8:_ (stop) global warming we should make immediate and __小题9:__(continue) efforts. We hope the situation will soon change. Global warming catches and holds our concern，_小题10:__ it affects us and will affect our later generations. We cannot wait any longer. Do it right. Do it right now.
查看答案
问答题 简答题

船舶空气调节系统的作用及其分类是什么？
查看答案