Question

已知集合A={(x,y )|y=x^-4x+3},集合B={(x,y )|y=x^-2x-2},求AUB

Answer 1

集合A={(x,y )|y=x^-4x+3},

y=x^-4x+3=(x-2)^2-1≥-1

集合B={(x,y )|y=x^-2x-2},

y=x^-2x-2=(x-1)^2-3≥-3

AUB={x,y/ y≥-3}