求其中D是由曲线与直线所围成的有界平面区域.
解:由于积分区域D关于y轴对称,因此
记为区域D在第一象限的部分,则
所以
Goods are carried by several of transport--on road or rail, by sea or air.
You can _____ some bottles of wine, or some chocolates, or a bunch of flowers.
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
2002年新配方口服补液盐(ORS)溶液的张力是
免费的网站请分享给朋友吧