设平面薄片[img=15x19]1803d671645ec07.png[/img]是由直线[img=75x22]1803d6716c77154.png[/img]与两坐标轴所围成的闭区域，其密度函数为[img=101x27]1803d671748564c.png[/img]，则该平面薄片的质心坐标为（ ）．
A: [img=54x51]1803d6717edc1eb.png[/img]
B: [img=54x51]1803d67186ed1f4.png[/img]
C: [img=54x51]1803d6718ef45e2.png[/img]
D: [img=54x51]1803d67196b32a9.png[/img]
A: [img=54x51]1803d6717edc1eb.png[/img]
B: [img=54x51]1803d67186ed1f4.png[/img]
C: [img=54x51]1803d6718ef45e2.png[/img]
D: [img=54x51]1803d67196b32a9.png[/img]
举一反三
- 设平面薄片[img=15x19]1802cebc4277da5.png[/img]是由直线[img=75x22]1802cebc4c12403.png[/img]与两坐标轴所围成的闭区域，则该平面薄片的形心坐标为（ ）． A: [img=54x51]1802cebc545ca9a.png[/img] B: [img=54x51]1802cebc5db251a.png[/img] C: [img=54x51]1802cebc6676f89.png[/img] D: [img=54x51]1802cebc6ed73f8.png[/img]
- 设平面薄片[img=15x19]180396c25d0c59f.png[/img]是由直线[img=75x22]180396c2648da44.png[/img]与两坐标轴所围成的闭区域，则该平面薄片的形心坐标为（ ）． A: [img=54x51]180396c26d035e3.png[/img] B: [img=54x51]180396c275a25e0.png[/img] C: [img=54x51]180396c27f3a557.png[/img] D: [img=54x51]180396c2877ac88.png[/img]
- 曲线[img=208x43]1803a57886836b6.png[/img]的图形在点[img=39x25]1803a5788f8a338.png[/img]处切线与ｘ轴交点的坐标是（ ） A: [img=70x51]1803a578983bf49.png[/img] B: [img=53x25]1803a578a0e74ed.png[/img] C: [img=54x51]1803a578a93d47d.png[/img] D: [img=39x25]1803a578b1fd48a.png[/img]
- 设平面区域D由直线[img=44x43]1803d9d8771a4d3.png[/img]及直线[img=149x26]1803d9d88003093.png[/img]所围成，二维随机变量(X,Y)在区域D上服从均匀分布，则X的边缘密度函数在x[img=44x18]1803d9d88890063.png[/img]处的值为 A: [img=9x43]1803d9d89194f0b.png[/img] B: [img=9x43]1803d9d89a45bee.png[/img] C: [img=9x18]1803d9d8a3b6a1e.png[/img] D: [img=9x43]1803d9d8ad43a85.png[/img]
- 1.设随机变量X的密度为[img=186x61]18034ea953ec9dd.png[/img]则常数A=________，概率[img=146x25]18034ea95d30d08.png[/img]__________. A: A=2，P(X>1|X<2)=[img=39x24]18034ea9659b618.png[/img] B: A=-2，P(X>1|X<2)=[img=39x24]18034ea9659b618.png[/img] C: A=2，P(X>1|X<2)=[img=47x44]18034ea9768a8c2.png[/img] D: A=-2，P(X>1|X<2)=[img=47x44]18034ea9768a8c2.png[/img]