题目
提问三道数学题
1.S is a set of n consecutive integers.比较the mean of S与the median of S大小 答案是一样大
我知道Mean=(a1+an)/2,当n=2k时,median=(ak+ak+1)/2;当n=2k+1时,median=ak+1,问题是怎么比较出mean和median想等的?(n,k,k+1均为a的角标)
2.If 9 trees are originally planted in a
circular pattern(就是9个点围成一个圆圈),what is the least number of trees that
must be transplanted so that the 9 trees will be in 2 straight rows?
咋做?答案是9-2*2=5,这是啥意思?(此题的图无法上传,若实在不明题意,就不必回答)
3.A rectangular rug covers half of a
rectangular floor that is 9 feet wide and 12 feet long.If the dimensions of the
rug are in the same ratio as those of the floor,how many feet long is the rug?答案是6根号下2
请问既然rug盖住floor一半,为何不能认为其长或宽是floor的一半?而是非要通过面积一半来算?
1.S is a set of n consecutive integers.比较the mean of S与the median of S大小 答案是一样大
我知道Mean=(a1+an)/2,当n=2k时,median=(ak+ak+1)/2;当n=2k+1时,median=ak+1,问题是怎么比较出mean和median想等的?(n,k,k+1均为a的角标)
2.If 9 trees are originally planted in a
circular pattern(就是9个点围成一个圆圈),what is the least number of trees that
must be transplanted so that the 9 trees will be in 2 straight rows?
咋做?答案是9-2*2=5,这是啥意思?(此题的图无法上传,若实在不明题意,就不必回答)
3.A rectangular rug covers half of a
rectangular floor that is 9 feet wide and 12 feet long.If the dimensions of the
rug are in the same ratio as those of the floor,how many feet long is the rug?答案是6根号下2
请问既然rug盖住floor一半,为何不能认为其长或宽是floor的一半?而是非要通过面积一半来算?
提问时间:2020-11-03
答案
1假设有K个连续整数,当K为偶数 时,其平均值为(1+K)/2,中位数为[K/2+(K/2+1)]/2=(1+K)/2
当K为奇数时,平均值为(1+K)/2,中位数为(K+1)/2所以两者相等.
2看不明白.
3题目是说毯子和地板是长宽等比例的,所以毯子的长为地板长度除以根号2等于6根号2.
当K为奇数时,平均值为(1+K)/2,中位数为(K+1)/2所以两者相等.
2看不明白.
3题目是说毯子和地板是长宽等比例的,所以毯子的长为地板长度除以根号2等于6根号2.
举一反三
已知函数f(x)=x,g(x)=alnx,a∈R.若曲线y=f(x)与曲线y=g(x)相交,且在交点处有相同的切线,求a的值和该切线方程.
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
奥巴马演讲不用看稿子.为什么中国领导演讲要看?
想找英语初三上学期的首字母填空练习……
英语翻译
最新试题
热门考点
- 1人生活中哪些地方需要动物帮助
- 2泡茶时茶叶不浮起来是好茶叶?为什么?
- 3两个相等的钝角有一个公共的顶点和一条公共边,并且两个角的另一条边所成的叫为90度,求钝角的大小
- 4根据句意写词语:( ):比喻因受惊恐儿警觉很灵敏的人.也只惊慌失措的样子
- 5英语作文《I want to be a reporter》(我想成为一名记者?)词量:80字左右.
- 6please keep away from the flowers什么意思
- 7六星瓢虫是害虫吗?
- 8根据a×b=c×d下面不能组成比例的是( ) A.a:c和d:b B.d:a和b:c C.b:d和a:c D.a:d和c:b
- 9钠和氧气反应氧化剂和还原剂是什么
- 10Peter ( ) (ansuer) the phone.括号里填什么