温故知新 1.离散型随机变量的定义可能取值为有限个或可以一一列举的随机变量,我们称为离散型随机变量.通常用大写英文字母表示随机变量,例如X,Y,Z;用小写英文字母表示随机变量的取值,例如x,y,z.随机变量的特点: 试验之前可以判断其可能出现的所有值,在试验之前不可能确定取何值;可以用数字表示2、随机变量的分类①离散型随机变量:X的取值可一、一列出;②连续型随机变量:X可以取某个区间内的一切值随机变量将随机事件的结果数量化.3、古典概型:①试验中所有可能出现的基本事件只有有限个;②每个基本事件出现的可能性相等。二、探究新知探究1.抛掷一枚骰子,所得的点数X有哪些值?取每个值的概率是多少? 因为X取值范围是{1,2,3,4,5,6}而且"P(X=m)"=1/6,m=1,2,3,4,5,6.因此X分布列如下表所示
1.对称性与首末两端“等距离”的两个二项式系数相等,即C_n^m=C_n^(n"-" m).2.增减性与最大值 当k(n+1)/2时,C_n^k随k的增加而减小.当n是偶数时,中间的一项C_n^(n/2)取得最大值;当n是奇数时,中间的两项C_n^((n"-" 1)/2) 与C_n^((n+1)/2)相等,且同时取得最大值.探究2.已知(1+x)^n =C_n^0+C_n^1 x+...〖+C〗_n^k x^k+...+C_n^n x^n 3.各二项式系数的和C_n^0+C_n^1+C_n^2+…+C_n^n=2n.令x=1 得(1+1)^n=C_n^0+C_n^1 +...+C_n^n=2^n所以,(a+b)^n 的展开式的各二项式系数之和为2^n1. 在(a+b)8的展开式中,二项式系数最大的项为 ,在(a+b)9的展开式中,二项式系数最大的项为 . 解析:因为(a+b)8的展开式中有9项,所以中间一项的二项式系数最大,该项为C_8^4a4b4=70a4b4.因为(a+b)9的展开式中有10项,所以中间两项的二项式系数最大,这两项分别为C_9^4a5b4=126a5b4,C_9^5a4b5=126a4b5.答案:1.70a4b4 126a5b4与126a4b5 2. A=C_n^0+C_n^2+C_n^4+…与B=C_n^1+C_n^3+C_n^5+…的大小关系是( )A.A>B B.A=B C.A<B D.不确定 解析:∵(1+1)n=C_n^0+C_n^1+C_n^2+…+C_n^n=2n,(1-1)n=C_n^0-C_n^1+C_n^2-…+(-1)nC_n^n=0,∴C_n^0+C_n^2+C_n^4+…=C_n^1+C_n^3+C_n^5+…=2n-1,即A=B.答案:B
1.确定研究对象,明确哪个是解释变量,哪个是响应变量;2.由经验确定非线性经验回归方程的模型;3.通过变换,将非线性经验回归模型转化为线性经验回归模型;4.按照公式计算经验回归方程中的参数,得到经验回归方程;5.消去新元,得到非线性经验回归方程;6.得出结果后分析残差图是否有异常 .跟踪训练1.一只药用昆虫的产卵数y与一定范围内的温度x有关,现收集了6组观测数据列于表中: 经计算得: 线性回归残差的平方和: ∑_(i=1)^6?〖(y_i-(y_i ) ?)〗^2=236,64,e^8.0605≈3167.其中 分别为观测数据中的温度和产卵数,i=1,2,3,4,5,6.(1)若用线性回归模型拟合,求y关于x的回归方程 (精确到0.1);(2)若用非线性回归模型拟合,求得y关于x回归方程为 且相关指数R2=0.9522. ①试与(1)中的线性回归模型相比较,用R2说明哪种模型的拟合效果更好 ?②用拟合效果好的模型预测温度为35℃时该种药用昆虫的产卵数.(结果取整数).
过程: 一. Greeting Hello ,how are you ? What ‘s the weather like today ? What the day is today ? 二. Warming 《The sun》、《The moon》 三. 新授 1. Gue What’s in the bag ? It’s …… They are …… 2.One by one
【教学目标】 1.了解诗歌意象,读出诗歌意境。2.在诵读中理解诗人的情感,感受诗歌的艺术魅力。3.能够在朗诵时通过重音、停连、节奏等,把握诗歌的感情基调,读出感情,读出韵律。【教学课时】1课时【教学过程】一、自由吟诵,导入新课师:“腹有诗书气自华”,读诗可以陶冶情操,丰富文化内涵,还可以提升气质。大家从小就开始接触诗歌,诗歌应该怎样去吟诵呢?哪位同学愿意为大家示范一下?(生朗诵诗歌)师:这位同学刚才朗诵得很好,但是还没有将诗歌的情感完全读出来。那么,我们该如何通过诵读,读出诗歌的意境、诗人的情感呢?今天,我们就一起来探讨一下诗歌的吟诵方法。【设计意图】活跃课堂气氛,提高学生参与度,对于训练诗歌朗诵是很有必要的。以学生吟诵诗歌的方式导入新课,可以较大程度地激发他们的学习兴趣。
幂函数是在继一次函数、反比例函数、二次函数之后,又学习了单调性、最值、奇偶性的基础上,借助实例,总结出幂函数的概念,再借助图像研究幂函数的性质.课程目标1、理解幂函数的概念,会画幂函数y=x,y=x2,y=x3,y=x-1,y=x 的图象;2、结合这几个幂函数的图象,理解幂函数图象的变化情况和性质;3、通过观察、总结幂函数的性质,培养学生概括抽象和识图能力.数学学科素养1.数学抽象:用数学语言表示函数幂函数;2.逻辑推理:常见幂函数的性质;3.数学运算:利用幂函数的概念求参数;4.数据分析:比较幂函数大小;5.数学建模:在具体问题情境中,运用数形结合思想,利用幂函数性质、图像特点解决实际问题。重点:常见幂函数的概念、图象和性质;难点:幂函数的单调性及比较两个幂值的大小.
GuangzhouUniversity 211Market Management GPA:3.6 UNDERGRADFinancial Accounting Double DegreeHonor award::In 2015 won the school class"three good students" (# People Award) ;GPA3.5, top student, 2016;2018 English competition, won thesecond prize, ranked the first school;
一个人的灵魂总是会在他的眼睛和语言里得到表露。灵魂高尚者,眼光明亮,语言高雅。反过来,我们也可以通过个人的眼睛和语言而窥视到他的灵魂,眼神淫邪,语言污秽,他的灵魂必定卑鄙肮脏。修改指导:这段论述用正反双向说理的方法阐明了一个人的灵魂、眼睛、语言三者之间的关系,条理清楚,语言简明,从思维和阐述上来看,应该说是准确严密的。但是,我们可以将语言润色,使原文变得更好。修改示例:灵魂储藏在人的心中,闪动在人的眼里,表露在人的嘴上。眼睛足以传情。它毫不掩饰地展现出你的学识、品性和情操:也许你貌不惊人,眼小如豆,但它却可以流露出华美的气质;也许你美目流盼,但却可能有一个蜷曲衰败的灵魂在其中沉睡。师:精妙地运用动词,恰到好处地使用比喻、对比等修辞手法,巧妙地使用假设句式,使文章在阐释事理的同时也不乏生动形象。【设计意图】把握了习作的要求后,给学生几个片段尝试修改。学生先从“言”和“意”等方面来进行修改,教师再具体示范指导,为综合修改全文做准备。
Choose the best choice fromA to F to finish the dialogue. You have one more answer. Each choice should beused only once.A: Hello, I’m a schoolnewspaper reporter. May I ask you some questions?B: ____46____
B: It’s about theexperiments three astronauts are doing on the space station.A: That’s great. I’minterested in space, so I want to be an astronaut like them.
There are many kinds ___21___art forms in China. ___22___ you often see any of them in your life?They help us understand and enjoy the traditional Chinese culture. When theSpring Festival comes, some people often ___23___ the red paper intodifferent art works with scissors.
Tim: _______36_______,Bob.Bob: Good afternoon, Tim. Icalled you just now, but nobody answered. _______37_______?Tim: I went to the cinema.And I watched a movie named The Battle atLake Changjin.Bob: Oh, great. It’s very famous nowadays. _______38_______?
On a snowy day, there was a man walking in ahurry on the road. His clothes were in poor condition. You might think he was abeggar(乞丐),but in fact he was a painter. His name was Vincent Willem van Gogh.
I often use old clothes that people don’t wearany more to make bags. I opened a small shop in my community and set up awebsite to sell the bags online. Many customers think they are fantastic. Now Iplan to write a new book about ways to use old clothes.
Remember that it’s better to fail than it’s togive up, and the key is to learn from your failure(失败). But along withdifficulties, there will also be ____18____ wonderful waiting for you.
Michelle,a famous lady, has found that more than 25% students are too fat in hercountry. It is a very serious problem. So she starts a Health Program to dealwith it. The Health Program is to reduce the number of fat students today andin the future.
I often hear some students say English isdifficult, so they can’t learn it well. ___11___ English is very easy for me. I’m good ___12___ it. I’m very glad to tell you ___13___ about how I study English.
Theoil paper umbrella is a traditional Chinese handicraft(手工艺品).It has a history of over 1,000 years in China.In early TangDynasty, it was introduced to Japan and Korea, so it was called the “TangUmbrella”. Later oil paper umbrellas were spread to other Asian countries, suchas Vietnam, Thailand and Laos, and each had its own style. However, assteel-ribbed(钢骨的)umbrellas appeared in the last century, thehand-made oil paper umbrellas became less used in daily life. They were turnedinto decorative artifacts(装饰性工艺品).
___14___, I think an interest in Englishis very important. When I was in Grade Three, we had a new ___15___ — English,it was new for me. I was interested in it. I worked hard at it. Soon we had anEnglish exam and I got a very good mark. How ___16___ I was! After that,I learned English harder. Our English teacher often teaches us English songs,and ___17___ sound nice. I often think how interesting English is!
Bike-to-Work Day is held every year across North America on thethird Friday of May. It was started by the League of American Bicyclistsin 1956. Its aim is to promote (促进) the bicycle as a serious choice of getting toand from work. In today’s world where global warming is a serious issue, thebicycle is a perfect way of reducing our carbon (碳) footprint.