prep中两题求助，期待指教

maxwell5858

if X is positive, which of the following could be the correct ordring of 1/X,2X,X^2

1. x^2< 2x< 1/x

2.x^2 <1/x < 2x

3.2x < x^2 < 1/x

答案说1和2是对的        可是我带入数字去算，可是不对，不知道是不是忽略了什么，大家帮我看看

of the 60 animal on a farm ,2/3 are either pigs or cows, how many of the animals are cows?

1. farm has more than twice as many cows as it has pigs

2. the farm has more than 12 pigs,

答案是 C.    条件一是说牛比猪多两倍呢，还是说多两倍多？如果是多两倍，那么1就直接可以得到有多少牛？

maxwell5858

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jesuisdesole

第二道我原来问过，有个ＣＤＥＲ讲的很清楚

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=329157&page=2

连接

driftysnail

第一题：1： when 0<x<√2/2 时成立， 2 when √2/2 < x <1 时成立。 3 无解