解析:首先求得圆的半径长,然后求得P、Q、R到Q′的距离,即可作出判断.解:⊙O′的半径是r= 12+12=2,PO′=2>2,则点P在⊙O′的外部;QO′=1<2,则点Q在⊙O′的内部;RO′=(2-1)2+(2-1)2=2=圆的半径,故点R在圆上.方法总结:注意运用平面内两点之间的距离公式,设平面内任意两点的坐标分别为A(x1,y1),B(x2,y2),则AB=(x1-x2)2+(y1-y2)2.【类型四】 点与圆的位置关系的实际应用如图,城市A的正北方向50千米的B处,有一无线电信号发射塔.已知,该发射塔发射的无线电信号的有效半径为100千米,AC是一条直达C城的公路,从A城发往C城的客车车速为60千米/时.(1)当客车从A城出发开往C城时,某人立即打开无线电收音机,客车行驶了0.5小时的时候,接收信号最强.此时,客车到发射塔的距离是多少千米(离发射塔越近,信号越强)?(2)客车从A城到C城共行驶2小时,请你判断到C城后还能接收到信号吗?请说明理由.
我们知道圆是一个旋转对称图形,无论绕圆心旋转多少度,它都能与自身重合,对称中心即为其圆心.将图中的扇形AOB(阴影部分)绕点O逆时针旋转某个角度,画出旋转之后的图形,比较前后两个图形,你能发现什么?二、合作探究探究点:圆心角、弧、弦之间的关系【类型一】 利用圆心角、弧、弦之间的关系证明线段相等如图,M为⊙O上一点,MA︵=MB︵,MD⊥OA于D,ME⊥OB于E,求证:MD=ME.解析:连接MO,根据等弧对等圆心角,则∠MOD=∠MOE,再由角平分线的性质,得出MD=ME.证明:连接MO,∵ MA︵=MB︵,∴∠MOD=∠MOE,又∵MD⊥OA于D,ME⊥OB于E,∴MD=ME.方法总结:圆心角、弧、弦之间相等关系的定理可以用来证明线段相等.本题考查了等弧对等圆心角,以及角平分线的性质.
第一课时: 一、活动准备: 1、幼儿园的背景图 2、儿歌中的动物图片 3、字卡 二、活动过程: (一)导入:师生谈话 1、小朋友们喜欢幼儿园吗? 2、表扬班上高高兴兴上幼儿园的小朋友,引出儿歌中的小动物。
1、对春联产生兴趣,乐于交流自己的发现。 2、大胆探索并发现春联的特征和种类,体验张贴春联的的乐趣。 3、初步了解春联的演变。 【活动准备】 物质准备: 1、春节里幼儿与家长一起贴春联的照片。 2、红纸、毛笔、砚台等。 经验准备: 1、幼儿有贴春联的经验 2、了解春联的由来和传说。 3、联系会写春联的家长助教
老师们,同学们,大家上午好!今天我国旗下讲话的主题是:学“八礼四仪”,让文明传承。全国都在开展文明礼仪养成教育,强调要突出抓好未成年人的“八礼四仪”,具体包括仪表之礼、餐饮之礼、言谈之礼、待人之礼、行走之礼、观赏之礼、游览之礼、仪式之礼这八个方面的礼仪教育。四仪是指7岁入学仪式;10岁成长仪式;14岁青春仪式;18岁成人仪式。这套“八礼四仪”融入了“爱、善、诚、勤、俭、美”六种理念和价值取向,注重从生活细节入手,未成年人易懂易学易做。“八礼四仪”是传承文明的需要。古老的中华民族自古以来就享有“礼仪之邦”的美称。在五千年悠久的历史长河中,不但创造了灿烂的文化,而且形成了古老民族的传统美德,很多优良的、传统的礼仪规范,直至今天仍然有很强大的生命力,它是中华民族的宝贵的精神财富。
2、发展幼儿的观察力和绘画表现能力。3、加深幼儿对老师的热爱之情。二、活动准备:1、请配班老师配合上课。2、带花边的纸或一次性纸餐盘若干、彩笔。三、活动过程:1、引出教师节,导入活动,引起幼儿兴趣。教师:小朋友,我们班上有几位老师?你们怎样称呼她们?明天就是教师节了,今天我们给老师画张像,画好后,送给老师好不好?
活动目标:l、通过游戏活动,发展幼儿走跑交替、跳跃及平衡的能力,体验游戏带来的乐趣。2、通过游戏活动,发展幼儿四肢的协调性、柔韧性和动作的灵敏性,提高幼儿听信号做相应动作的能力。3、培养幼儿的扩散性思维和协作能力。 活动准备:l、红、黄、蓝、绿色的塑料圈每人四个。2、红、黄、蓝、绿色的小旗各一面。3、大鼓一面,柱子两根。4、录音机、磁带。5、场地布置如图。
2,在“数高楼”这一音乐游戏中,培养幼儿打击4/4,2/4拍音乐的节奏,并在此基础上进行一2/4拍乐曲的节奏的不同打法。 3,培养幼儿的协商合作能力,及音乐表现力。准备:1、画有楼房的表格2张,空表格3—6张及若干可用于粘贴的楼房画; 2、录音机 数高楼的音乐磁带过程:(一)听《铃儿响叮当》音乐幼儿坐到位置上; 1、发声练习 提醒幼儿用轻声,并将身体坐正; 2、复习歌曲《数高楼》 指出其中不足之处。
In the late autumn, John was badly ill andbecame bedridden (长期卧床的).After the doctor visited John several times, he told Sue, “His condition isquite ___22___.John seems to have lost all will to live. If he doesn’t want to live, medicineswill not help him.”
In the large yard stood thirteen trees ofdifferent sizes. One day, while Joey was playing with his sister under thetrees, he noticed that a tree trunk (树干) had a sad look. He raninto the house to tell his mom about it. She told Joey to find the reason whyit was sad.
The app — called Sit With Us — is ___15___. If a student is having lunch in the afternoon,he or she can create an invitation. Other students can open the app and ___16___ that invitation. They can then use the app todecide when and where to ___17___.
Thinking that her dream could never come true,Kelly was in low spirits and ____18____ her studies at school. Hermother did all she could to cheer her up, ____19____ Kelly refused tochange. She even took out all her anger and ____20____ on her mother.
I joineda band (乐队)as a drummer in my middle school. I thought itwould be fun playing the drum and meeting new friends. At first it was easy,but a month later, it got difficult. I was the only one who couldn’t keep pace (节奏)with the other players. Our teacher,Angie, singled me out to keep practicing while everyone else got to relax. Ifelt ashamed (羞愧的)as my teammates watched me fail so many times.Finally I got so tired of practicing that I didn’t care about doing it right.
When itcomes to a meaningful life, we might think of love, happiness and health. Alife filled with meaning is what most of us want for ourselves. Then, whatmakes a meaningful life?Manyresearchers agree that a meaningful life comes down to three factors (因素): havinglong-term goals, believing that one’s life matters, and feeling that one’s lifefits together and “makes sense”.But we believe there is more to consider. Sometimeslife enables us to experience small moments of beauty. When people are open toappreciating (欣赏) suchexperiences, these moments may improve how they see their own life. We callthis experiential appreciation (EA).
YangHongwei, 56, was born into a kite-making family in Weifang. When she was young,she often saw kites with bright colors and different shapes in hergrandfather’s workshop.
In the large yard stood thirteen trees ofdifferent sizes. One day, while Joey was playing with his sister under thetrees, he noticed that a tree trunk (树干) had a sad look. He raninto the house to tell his mom about it. She told Joey to find the reason whyit was sad.
As a boy, Kevin visited national parks and helearned the Earth is in ___12___ condition. He felt worried, and hewanted to ___13___ the Earth. In 2009, he went to swim in water nearNorth Pole(北极)todraw people’s attention to the melting glaciers(融化的冰川).
Long ago, a poor old couple lived on the coast.One day, an old storyteller came to their village. The old couple gave him ameal. In return, he gave them a coffee mill (磨粉机)and said, “Say, ‘Mill, please grind (磨粉)’,”
As a boy, Kevin visited national parks and helearned the Earth is in ___12___condition. He felt worried, and he wanted to ___13___ the Earth. In 2009, he went to swim in waternear North Pole(北极)todraw people’s attention to the melting glaciers(融化的冰川).
At the age of nine, Kelly dreamed of being abasketball player. But one day when she was playing basketball, she hurt herleft leg ____16____.
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