以下是引用wangxiaoqing在2009-3-26 2:45:00的发言:2ds: X<0? 1. X^2<X^3 2. X^3<X^4 选 B 1: x^2-x^3<0 x^2(1-x)<0 the critical point is 0 and 1 for x>1, the expression is <0 for 0<x<1, the expression is >0 for x<0, the expression is >0 so x>1, so x>0 not x<0, so the question can be answered 2: x^3(1-x)<0 the critical point is 0 and 1 for x>1, the expression is <0 for 0<x<1, the expression is >0 for x<0, the expression is <0 so x>1 or x<0, not sure if X>0 or not so the answer should be A
昂 我条件写错了 应该是1.X^2>X^3 2.X^3>X^4 |