Question

设集合A=｛x|y=log2(x-1)},B={y|y=-x^2+2x-2,x属于R}求A∩B

Answer 1

A=｛x|y=log2(x-1)},x-1＞0，x＞1
B={y|y=-x^2+2x-2,x属于R}
y=-x^2+2x-2=-（x+1）^2-1
y≤-1
所以A∩B为空集

Answer 2

A={x|y=log2(x-1)}={x|x＞1}

y=-x²+2x-2=-(x-1)²-1≤-1
B={y|y=-x²+2x-2,x∈R}={y|y≤-1}

所以A∩B=空集

Answer 3

A∩B={x| x >1}