Question

设集合M={y|y=x²-3,x∈R},N={y|y=-2x²+1,x∈R},求M∩N,M∪N

Answer 1

y=x²-3≥3
y=-2x²+1≤1
M∩N=空集
M∪N=={y|y≥3或y≤1}