设f(x,y)在点(0,0)附近有定义,且,则
Forthenewcountrytosurvive,________foritspeopletoenjoyprosperity,neweconomicpolicieswillberequired.
Ihavebeenstudyinghereforfouryears,bynextsummerI________.
设平面区域,则D绕y轴旋转所成旋转体体积为_____
设随机变量(X,Y)服从二维正态分布N(0,0;1,4;-1/2),随机变量中服从标准正态分布且与X独立的是()
