已知int x=3,y=4;，写出下列表达式的值 (1) (x,y) (2) x>y?x:y (3) x?y:x (4) (x>y)?(y>=2)?1:2:(y>x)?x:y

已知点()(()-()1(),()y()1())(),()(2(),()y()2())(),()(()-()3(),()y()3())()都在函数()y()=()x()2()的图象上,则()()A.()y()1()<()y()2()<()y()3()B.()y()1()<()y()3()<()y()2()C.()y()3()<()y()2()<()y()1()D.()y()2()<()y()1()<()y()3

设(X,Y)的联合概率密度函数为[img=229x53]18032cef146518f.png[/img]则以下选项正确的是 A: 当{Y=0.5}时，X在区间(0.5,1)服从均匀分布. B: P(X>0.5｜Y=1/4)=2/3. C: P(Y<1/2｜X=3/4)=4/9. D: P(Y<1/3｜X=2/3)=1/3. E: P(Y<1/6｜X=1/3)=1/2. F: P(X>2/3｜Y=1/3)=1/3. G: P(X>3/8｜Y=3/4)=3/8. H: 当{X=0.5}时，Y在区间(0,0.5)服从均匀分布. I: 当{Y=0.8}时，X在区间(0,0.8)服从均匀分布.

已知y与x成正比例，如果x＝2时y＝1，x＝3时y是（）． A: 1.5 B: 2 C: 3 D: 6

方程${{x}^{2}}{{y}^{''}}-(x+2)(x{{y}^{'}}-y)={{x}^{4}}$的通解是( ) A: $y={{C}_{1}}x+{{C}_{2}}{{e}^{x}}-(\frac{1}{2}{{x}^{3}}+{{x}^{2}})$ B: $y={{C}_{1}}x+{{C}_{2}}{{e}^{x}}-(\frac{1}{2}{{x}^{3}}+{{x}^{4}})$ C: $y={{C}_{1}}x+{{C}_{2}}x{{e}^{x}}-(\frac{1}{2}{{x}^{3}}+{{x}^{4}})$ D: $y={{C}_{1}}x+{{C}_{2}}x{{e}^{x}}-(\frac{1}{2}{{x}^{3}}+{{x}^{2}})$