• 2021-04-14
    设A={(x,y)2223x-y=1},B={(x,y)2223x+y=9},则A2229B=
  • {(5,4)}

    内容

    • 0

      设A={{x,y},Φ,x,y},则A-{x,y}={}

    • 1

      设D(X)=1,p(Y)=9,ρXY=一0.3,则Cov(X,Y)=___________.

    • 2

      设y=y(x)满足(1+x2)y’=xy且y(0)=1,则y(x)=________.

    • 3

      include <;stdio.h>;void main(){int x = 1, y = 10;do{y -= x;x++;}while ( y <; 0 );printf( “\nx=%d, y=%d”, x, y );}结果为: A: x=2,y=9 B: 2,9 C: x=1,y=9 D: x=1,y=10

    • 4

      设A={(x,y)|y=-4x+6},B={(x,y)|y=5x-3},则A∩B=(  ) A: {1,2} B: {(1,2)} C: {x=1,y=2} D: (1,2)