Question

设集合M={x|x^2-x-2<0},N={x|x^2+x-2<0}则M∩N=

答案{x|x^2-1<0}

Answer 1

M: (x-2)(x+1)<0, 即-1<x<2
N: (x+2)(x-1)<0, 即-2<x<1
则M∩N={ x| -1<x<1}