Art museums are places where people can learn about various cultures. The increasingly popular “design museums” that are opening today, however, perform quite a different role. Unlike most art mus
Wind is the great maker of waves. There are exceptions, such as the tidal(潮汐的) waves some??times produced by earthquakes under the sea. But the waves most of us know are produced by winds blowin
的二次项系数为
，且不等式
的解集为
，若
，求
即
解集为
且
，
，即
………………………………………..12分