函数f(x，y)=ln(9-x2-y2)/√(x2+y2-4)的定义域是()
A.{(x，y)∣2﹤x2+y2﹤3}
B.{(x，y)∣4﹤x2+y2﹤9}
C.{(x，y)∣4﹤x2+y2≤9}
D.{(x，y)∣2﹤x2+y2≤3}
正确答案B 
函数f(x，y)=ln(9-x2-y2)/√(x2+y2-4)的定义域是()
A.{(x，y)∣2﹤x2+y2﹤3}
B.{(x，y)∣4﹤x2+y2﹤9}
C.{(x，y)∣4﹤x2+y2≤9}
D.{(x，y)∣2﹤x2+y2≤3}
正确答案B 