Question

已知集合A={y|y=x平方-2x-1,x∈R},B={y|y=-x平方+2x+15,x属于R},则A交B=?

Answer 1

A={y|y=x^2-2x-1,x∈R}={y|y=(x-1)^2-2}={y|y>=-2}

B={y|y=-x^2+2x+15,x∈R}={y|y=-(x-1)^2+16}={y|y