MATH

janep78

问找一群人中女的概率 1.给出男女比例 2.给出了找不出的概率 d why??? x<>0.问!X!>1吗? 1.X/!X!X 某人存钱,不取,按季复利,笫二季利息>100? 1.第一季有100利息 2.第3季有大于100的利息

lisaislisa

1. 1)as we know x:y we can get x/(x+y) 2)as we know P(notA) we can get P(A) 2.A 1)=> x as X is smaller than itself when it times the absolute value of itself !x! must be >1 2)=> !x!>x whenever x<0 but we can not say if it's <-1 or not eg x=-2 or x=-1/2 3. A 1)as it is the compound interest the interest gain growing as the time going therefore in the second period , the interest is more than that in the first 2)we don't know the interest rate or how much it is more than 100 in the third period , therefore , whether we get more than 100 for the 2nd period is hard to say ^^

isenetlab12

x<>0.问|X|>1吗? 1.X/|X|X the answer should be C for 1, if X<0, then -10, then 11 for 2, we know X<0 then the anser is C Correct?

onlyangel

第二题同意c，思路同楼上！
如果按照答案是a，可以举出反例，x=2或-1/2，a 都成立
这种不等式乘乘除除绝对值的题目，一定要分开考虑大于零和小于零，不等号会变方向哟！一步一步算不要急！

卧室春竹

第二个应该是c 第二个条件说明了 x<0 然后 第一个条件 x就可以移项了。。。。。。^_^

[此贴子已经被作者于2003-1-9 17:42:25编辑过]