When a vector field satisfies ( ), it can be expressed by the gradient of a scalar field.
A: [img=95x37]1803b96a67f7f7c.png[/img]
B: [img=87x36]1803b96a6fd7092.png[/img]
C: [img=129x51]1803b96a77abc30.png[/img]
D: [img=100x42]1803b96a7efa2a8.png[/img]
A: [img=95x37]1803b96a67f7f7c.png[/img]
B: [img=87x36]1803b96a6fd7092.png[/img]
C: [img=129x51]1803b96a77abc30.png[/img]
D: [img=100x42]1803b96a7efa2a8.png[/img]
举一反三
- 设随机变量（X,Y）的联合密度函数为 [img=296x65]180348098079cc8.png[/img],则概率P{X>=3,Y<=2}=? A: 1/6 B: 1/36 C: 1/96 D: 7/128
- 设随机变量（X,Y）的联合密度函数为[img=296x65]1803480cc787bae.png[/img],则概率P{X=3,Y=2}=? A: 1/6 B: 1/36 C: 1/96 D: 7/128
- 设随机变量（X,Y）的联合密度函数为 [img=296x65]18034a92690e2db.png[/img],则概率P{X>=3,Y<=2}=? A: 1/6 B: 1/36 C: 1/96 D: 7/128
- 计算行列式[img=110x83]18031758e7f5a2b.png[/img] A: 96 B: -96 C: -27 D: 27
- 计算行列式[img=110x83]1803df6b829e558.png[/img] A: 96 B: -96 C: -27 D: 27