若 X, Y，满足DX=DY=[img=18x22]1803dfef6dae947.png[/img]，E(XY)=EXEY，则D（X-2Y）的值是( )（A）2 [img=18x22]1803dfef6dae947.png[/img] （B）3 [img=18x22]1803dfef6dae947.png[/img] （C）4 [img=18x22]1803dfef6dae947.png[/img] （D）5[img=18x22]1803dfef6dae947.png[/img]
A: 2 [img=18x22]1803dfef98590fb.png[/img]
B: 3 [img=18x22]1803dfef98590fb.png[/img]
C: 4 [img=18x22]1803dfef98590fb.png[/img]
D: 5[img=18x22]1803dfef98590fb.png[/img]
A: 2 [img=18x22]1803dfef98590fb.png[/img]
B: 3 [img=18x22]1803dfef98590fb.png[/img]
C: 4 [img=18x22]1803dfef98590fb.png[/img]
D: 5[img=18x22]1803dfef98590fb.png[/img]
举一反三
- 若 X, Y，满足DX=DY=[img=18x22]17de6024b9b2db4.png[/img]，E(XY)=EXEY，则D（X-2Y）的值是( )（A）2 [img=18x22]17de6024b9b2db4.png[/img] （B）3 [img=18x22]17de6024b9b2db4.png[/img] （C）4 [img=18x22]17de6024b9b2db4.png[/img] （D）5[img=18x22]17de6024b9b2db4.png[/img] 未知类型：{'options': ['2[img=18x22]17de6024b9b2db4.png[/img]', '3[img=18x22]17de6024b9b2db4.png[/img]', '4[img=18x22]17de6024b9b2db4.png[/img]', '5[img=18x22]17de6024b9b2db4.png[/img]'], 'type': 102}
- 下列4个集合中是空集的是（） A: ｛x|[img=18x22]1802f060e2f728f.png[/img]+1=0｝ B: ｛x|[img=18x22]1802f060e2f728f.png[/img]<-x｝ C: ｛x|[img=18x22]1802f060e2f728f.png[/img]=0｝ D: ｛x|[img=18x22]1802f060e2f728f.png[/img]-1=0｝
- 下列4个集合中是空集的是（） A: ｛x|[img=18x22]1803d021d498831.png[/img]+1=0｝ B: ｛x|[img=18x22]1803d021d498831.png[/img]<-x｝ C: ｛x|[img=18x22]1803d021d498831.png[/img]=0｝ D: ｛x|[img=18x22]1803d021d498831.png[/img]-1=0｝
- 下列4个集合中是空集的是（） A: ｛x|[img=18x22]1803d0240bcad39.png[/img]+1=0｝ B: ｛x|[img=18x22]1803d0240bcad39.png[/img]-x｝ C: ｛x|[img=18x22]1803d0240bcad39.png[/img]=0｝ D: ｛x|[img=18x22]1803d0240bcad39.png[/img]-1=0｝
- 若X ~ N(3,[img=18x22]1803392546fb4bb.png[/img] ) ，且P{X[img=14x21]180339254fafce9.png[/img]6}=0.9 ，则P{X<0}= ．