设F<sub>1</sub>(x)与F<sub>1</sub>(x)分别为随机变量X<sub>1</sub>与X<sub>2</sub>的分布函数,若函数F(x)=aF<sub>1</sub>(x)-bF<sub>2</sub>(x)是某随机变量的分布函数,则必有()
A、a=3/5,b=-2/5
B、a=-3/5,b=2/5
C、a=1/2,b=3/2
D、a=1/2,b=-3/2
A、a=3/5,b=-2/5
B、a=-3/5,b=2/5
C、a=1/2,b=3/2
D、a=1/2,b=-3/2
A、f(x<sub>0sub>)f″(x)>0 B、f(x<sub>0sub>)f′(x)>0 C、f(x<sub>0sub>)f″(x)<0 D、f(x<sub>0sub>)f′(x)<0
A、(x<sub>Wsub>,x<sub>Wsub>) B、(x<sub>Fsub>,x<sub>Fsub>) C、(x<sub>Dsub>,x<sub>Dsub>) D、(0,x<sub>Dsub>/(R+1))
A、P(x<sub>1sub>≤ξ≤x<sub>2sub>)=F(x<sub>2sub>)-F(x<sub>1sub>) B、(-x)=1-Φ(x) C、P(AB)=P(A)P(B) D、P(A+B)=P(A)+P(B)
A、必有F<sub>Rsub>=F<sub>1sub>+F<sub>2sub> B、不可能有F<sub>Rsub>=F<sub>1sub>+F<sub>2sub> C、必有F<sub>Rsub>>F<sub>1sub>,F<sub>Rsub>>F<sub>2sub> D、可能有F<sub>Rsub><F<sub>1sub>,F<sub>Rsub><F<sub>2sub>
A、e<sub>1sub>c<sub>1sub>F<sub>1sub>=e<sub>2sub>c<sub>2sub>F<sub>2sub> B、c<sub>1sub>F<sub>1sub>=c<sub>2sub>F<sub>2sub> C、c<sub>1sub>/c<sub>2sub>=F<sub>2sub>/F<sub>1sub> D、c<sub>1sub>/c<sub>2sub>=F<sub>1sub>/F<sub>2sub>
A、F<sub>1sub>=F<sub>2sub> B、F<sub>1sub>-F<sub>2sub>=F<sub>esub> C、F<sub>1sub>/F<sub>2sub>=efα D、F<sub>1sub>+F<sub>2sub>=F<sub>0sub>
A、f(x)在X=X<sub>0sub>处的值一定存在且等于极限值1623; B、f(x)在X=X<sub>0sub>处的值一定存在但不一定等于极限值1623; C、f(x)在X=X<sub>0sub>处的值不一定存在 D、如果f(x)在X=X<sub>0sub>处的极限存在,则一定等于极限值
A、F=x·y-x<sub>asub>·y<sub>asub>; B、F=x<sub>asub>·y-y<sub>asub>·x; C、F=x<sub>asub>·x-y<sub>asub>·y; D、F=x<sub>asub>+y<sub>asub>-x-y