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  • 人教版高中數(shù)學(xué)選擇性必修二數(shù)列的概念(1)教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選擇性必修二數(shù)列的概念(1)教學(xué)設(shè)計(jì)

    情景導(dǎo)學(xué)古語(yǔ)云:“勤學(xué)如春起之苗,不見(jiàn)其增,日有所長(zhǎng)”如果對(duì)“春起之苗”每日用精密儀器度量,則每日的高度值按日期排在一起,可組成一個(gè)數(shù)列. 那么什么叫數(shù)列呢?二、問(wèn)題探究1. 王芳從一歲到17歲,每年生日那天測(cè)量身高,將這些身高數(shù)據(jù)(單位:厘米)依次排成一列數(shù):75,87,96,103,110,116,120,128,138,145,153,158,160,162,163,165,168 ①記王芳第i歲的身高為 h_i ,那么h_1=75 , h_2=87, 〖"…" ,h〗_17=168.我們發(fā)現(xiàn)h_i中的i反映了身高按歲數(shù)從1到17的順序排列時(shí)的確定位置,即h_1=75 是排在第1位的數(shù),h_2=87是排在第2位的數(shù)〖"…" ,h〗_17 =168是排在第17位的數(shù),它們之間不能交換位置,所以①具有確定順序的一列數(shù)。2. 在兩河流域發(fā)掘的一塊泥板(編號(hào)K90,約生產(chǎn)于公元前7世紀(jì))上,有一列依次表示一個(gè)月中從第1天到第15天,每天月亮可見(jiàn)部分的數(shù):5,10,20,40,80,96,112,128,144,160,176,192,208,224,240. ②

  • 圓的一般方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    圓的一般方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    情境導(dǎo)學(xué)前面我們已討論了圓的標(biāo)準(zhǔn)方程為(x-a)2+(y-b)2=r2,現(xiàn)將其展開(kāi)可得:x2+y2-2ax-2bx+a2+b2-r2=0.可見(jiàn),任何一個(gè)圓的方程都可以變形x2+y2+Dx+Ey+F=0的形式.請(qǐng)大家思考一下,形如x2+y2+Dx+Ey+F=0的方程表示的曲線是不是圓?下面我們來(lái)探討這一方面的問(wèn)題.探究新知例如,對(duì)于方程x^2+y^2-2x-4y+6=0,對(duì)其進(jìn)行配方,得〖(x-1)〗^2+(〖y-2)〗^2=-1,因?yàn)槿我庖稽c(diǎn)的坐標(biāo) (x,y) 都不滿足這個(gè)方程,所以這個(gè)方程不表示任何圖形,所以形如x2+y2+Dx+Ey+F=0的方程不一定能通過(guò)恒等變換為圓的標(biāo)準(zhǔn)方程,這表明形如x2+y2+Dx+Ey+F=0的方程不一定是圓的方程.一、圓的一般方程(1)當(dāng)D2+E2-4F>0時(shí),方程x2+y2+Dx+Ey+F=0表示以(-D/2,-E/2)為圓心,1/2 √(D^2+E^2 "-" 4F)為半徑的圓,將方程x2+y2+Dx+Ey+F=0,配方可得〖(x+D/2)〗^2+(〖y+E/2)〗^2=(D^2+E^2-4F)/4(2)當(dāng)D2+E2-4F=0時(shí),方程x2+y2+Dx+Ey+F=0,表示一個(gè)點(diǎn)(-D/2,-E/2)(3)當(dāng)D2+E2-4F0);

  • 圓與圓的位置關(guān)系教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    圓與圓的位置關(guān)系教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    1.兩圓x2+y2-1=0和x2+y2-4x+2y-4=0的位置關(guān)系是( )A.內(nèi)切 B.相交 C.外切 D.外離解析:圓x2+y2-1=0表示以O(shè)1(0,0)點(diǎn)為圓心,以R1=1為半徑的圓.圓x2+y2-4x+2y-4=0表示以O(shè)2(2,-1)點(diǎn)為圓心,以R2=3為半徑的圓.∵|O1O2|=√5,∴R2-R1<|O1O2|<R2+R1,∴圓x2+y2-1=0和圓x2+y2-4x+2y-4=0相交.答案:B2.圓C1:x2+y2-12x-2y-13=0和圓C2:x2+y2+12x+16y-25=0的公共弦所在的直線方程是 . 解析:兩圓的方程相減得公共弦所在的直線方程為4x+3y-2=0.答案:4x+3y-2=03.半徑為6的圓與x軸相切,且與圓x2+(y-3)2=1內(nèi)切,則此圓的方程為( )A.(x-4)2+(y-6)2=16 B.(x±4)2+(y-6)2=16C.(x-4)2+(y-6)2=36 D.(x±4)2+(y-6)2=36解析:設(shè)所求圓心坐標(biāo)為(a,b),則|b|=6.由題意,得a2+(b-3)2=(6-1)2=25.若b=6,則a=±4;若b=-6,則a無(wú)解.故所求圓方程為(x±4)2+(y-6)2=36.答案:D4.若圓C1:x2+y2=4與圓C2:x2+y2-2ax+a2-1=0內(nèi)切,則a等于 . 解析:圓C1的圓心C1(0,0),半徑r1=2.圓C2可化為(x-a)2+y2=1,即圓心C2(a,0),半徑r2=1,若兩圓內(nèi)切,需|C1C2|=√(a^2+0^2 )=2-1=1.解得a=±1. 答案:±1 5. 已知兩個(gè)圓C1:x2+y2=4,C2:x2+y2-2x-4y+4=0,直線l:x+2y=0,求經(jīng)過(guò)C1和C2的交點(diǎn)且和l相切的圓的方程.解:設(shè)所求圓的方程為x2+y2+4-2x-4y+λ(x2+y2-4)=0,即(1+λ)x2+(1+λ)y2-2x-4y+4(1-λ)=0.所以圓心為 1/(1+λ),2/(1+λ) ,半徑為1/2 √((("-" 2)/(1+λ)) ^2+(("-" 4)/(1+λ)) ^2 "-" 16((1"-" λ)/(1+λ))),即|1/(1+λ)+4/(1+λ)|/√5=1/2 √((4+16"-" 16"(" 1"-" λ^2 ")" )/("(" 1+λ")" ^2 )).解得λ=±1,舍去λ=-1,圓x2+y2=4顯然不符合題意,故所求圓的方程為x2+y2-x-2y=0.

  • 人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量及其分布列(1)教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量及其分布列(1)教學(xué)設(shè)計(jì)

    4.寫出下列隨機(jī)變量可能取的值,并說(shuō)明隨機(jī)變量所取的值表示的隨機(jī)試驗(yàn)的結(jié)果.(1)一個(gè)袋中裝有8個(gè)紅球,3個(gè)白球,從中任取5個(gè)球,其中所含白球的個(gè)數(shù)為X.(2)一個(gè)袋中有5個(gè)同樣大小的黑球,編號(hào)為1,2,3,4,5,從中任取3個(gè)球,取出的球的最大號(hào)碼記為X.(3). 在本例(1)條件下,規(guī)定取出一個(gè)紅球贏2元,而每取出一個(gè)白球輸1元,以ξ表示贏得的錢數(shù),結(jié)果如何?[解] (1)X可取0,1,2,3.X=0表示取5個(gè)球全是紅球;X=1表示取1個(gè)白球,4個(gè)紅球;X=2表示取2個(gè)白球,3個(gè)紅球;X=3表示取3個(gè)白球,2個(gè)紅球.(2)X可取3,4,5.X=3表示取出的球編號(hào)為1,2,3;X=4表示取出的球編號(hào)為1,2,4;1,3,4或2,3,4.X=5表示取出的球編號(hào)為1,2,5;1,3,5;1,4,5;2,3,5;2,4,5或3,4,5.(3) ξ=10表示取5個(gè)球全是紅球;ξ=7表示取1個(gè)白球,4個(gè)紅球;ξ=4表示取2個(gè)白球,3個(gè)紅球;ξ=1表示取3個(gè)白球,2個(gè)紅球.

  • 直線的點(diǎn)斜式方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    直線的點(diǎn)斜式方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    【答案】B [由直線方程知直線斜率為3,令x=0可得在y軸上的截距為y=-3.故選B.]3.已知直線l1過(guò)點(diǎn)P(2,1)且與直線l2:y=x+1垂直,則l1的點(diǎn)斜式方程為_(kāi)_______.【答案】y-1=-(x-2) [直線l2的斜率k2=1,故l1的斜率為-1,所以l1的點(diǎn)斜式方程為y-1=-(x-2).]4.已知兩條直線y=ax-2和y=(2-a)x+1互相平行,則a=________. 【答案】1 [由題意得a=2-a,解得a=1.]5.無(wú)論k取何值,直線y-2=k(x+1)所過(guò)的定點(diǎn)是 . 【答案】(-1,2)6.直線l經(jīng)過(guò)點(diǎn)P(3,4),它的傾斜角是直線y=3x+3的傾斜角的2倍,求直線l的點(diǎn)斜式方程.【答案】直線y=3x+3的斜率k=3,則其傾斜角α=60°,所以直線l的傾斜角為120°.以直線l的斜率為k′=tan 120°=-3.所以直線l的點(diǎn)斜式方程為y-4=-3(x-3).

  • 直線的兩點(diǎn)式方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    直線的兩點(diǎn)式方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    解析:①過(guò)原點(diǎn)時(shí),直線方程為y=-34x.②直線不過(guò)原點(diǎn)時(shí),可設(shè)其方程為xa+ya=1,∴4a+-3a=1,∴a=1.∴直線方程為x+y-1=0.所以這樣的直線有2條,選B.答案:B4.若點(diǎn)P(3,m)在過(guò)點(diǎn)A(2,-1),B(-3,4)的直線上,則m= . 解析:由兩點(diǎn)式方程得,過(guò)A,B兩點(diǎn)的直線方程為(y"-(-" 1")" )/(4"-(-" 1")" )=(x"-" 2)/("-" 3"-" 2),即x+y-1=0.又點(diǎn)P(3,m)在直線AB上,所以3+m-1=0,得m=-2.答案:-2 5.直線ax+by=1(ab≠0)與兩坐標(biāo)軸圍成的三角形的面積是 . 解析:直線在兩坐標(biāo)軸上的截距分別為1/a 與 1/b,所以直線與坐標(biāo)軸圍成的三角形面積為1/(2"|" ab"|" ).答案:1/(2"|" ab"|" )6.已知三角形的三個(gè)頂點(diǎn)A(0,4),B(-2,6),C(-8,0).(1)求三角形三邊所在直線的方程;(2)求AC邊上的垂直平分線的方程.解析(1)直線AB的方程為y-46-4=x-0-2-0,整理得x+y-4=0;直線BC的方程為y-06-0=x+8-2+8,整理得x-y+8=0;由截距式可知,直線AC的方程為x-8+y4=1,整理得x-2y+8=0.(2)線段AC的中點(diǎn)為D(-4,2),直線AC的斜率為12,則AC邊上的垂直平分線的斜率為-2,所以AC邊的垂直平分線的方程為y-2=-2(x+4),整理得2x+y+6=0.

  • 人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的方差教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的方差教學(xué)設(shè)計(jì)

    3.下結(jié)論.依據(jù)均值和方差做出結(jié)論.跟蹤訓(xùn)練2. A、B兩個(gè)投資項(xiàng)目的利潤(rùn)率分別為隨機(jī)變量X1和X2,根據(jù)市場(chǎng)分析, X1和X2的分布列分別為X1 2% 8% 12% X2 5% 10%P 0.2 0.5 0.3 P 0.8 0.2求:(1)在A、B兩個(gè)項(xiàng)目上各投資100萬(wàn)元, Y1和Y2分別表示投資項(xiàng)目A和B所獲得的利潤(rùn),求方差D(Y1)和D(Y2);(2)根據(jù)得到的結(jié)論,對(duì)于投資者有什么建議? 解:(1)題目可知,投資項(xiàng)目A和B所獲得的利潤(rùn)Y1和Y2的分布列為:Y1 2 8 12 Y2 5 10P 0.2 0.5 0.3 P 0.8 0.2所以 ;; 解:(2) 由(1)可知 ,說(shuō)明投資A項(xiàng)目比投資B項(xiàng)目期望收益要高;同時(shí) ,說(shuō)明投資A項(xiàng)目比投資B項(xiàng)目的實(shí)際收益相對(duì)于期望收益的平均波動(dòng)要更大.因此,對(duì)于追求穩(wěn)定的投資者,投資B項(xiàng)目更合適;而對(duì)于更看重利潤(rùn)并且愿意為了高利潤(rùn)承擔(dān)風(fēng)險(xiǎn)的投資者,投資A項(xiàng)目更合適.

  • 人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的均值教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選修3離散型隨機(jī)變量的均值教學(xué)設(shè)計(jì)

    對(duì)于離散型隨機(jī)變量,可以由它的概率分布列確定與該隨機(jī)變量相關(guān)事件的概率。但在實(shí)際問(wèn)題中,有時(shí)我們更感興趣的是隨機(jī)變量的某些數(shù)字特征。例如,要了解某班同學(xué)在一次數(shù)學(xué)測(cè)驗(yàn)中的總體水平,很重要的是看平均分;要了解某班同學(xué)數(shù)學(xué)成績(jī)是否“兩極分化”則需要考察這個(gè)班數(shù)學(xué)成績(jī)的方差。我們還常常希望直接通過(guò)數(shù)字來(lái)反映隨機(jī)變量的某個(gè)方面的特征,最常用的有期望與方差.二、 探究新知探究1.甲乙兩名射箭運(yùn)動(dòng)員射中目標(biāo)靶的環(huán)數(shù)的分布列如下表所示:如何比較他們射箭水平的高低呢?環(huán)數(shù)X 7 8 9 10甲射中的概率 0.1 0.2 0.3 0.4乙射中的概率 0.15 0.25 0.4 0.2類似兩組數(shù)據(jù)的比較,首先比較擊中的平均環(huán)數(shù),如果平均環(huán)數(shù)相等,再看穩(wěn)定性.假設(shè)甲射箭n次,射中7環(huán)、8環(huán)、9環(huán)和10環(huán)的頻率分別為:甲n次射箭射中的平均環(huán)數(shù)當(dāng)n足夠大時(shí),頻率穩(wěn)定于概率,所以x穩(wěn)定于7×0.1+8×0.2+9×0.3+10×0.4=9.即甲射中平均環(huán)數(shù)的穩(wěn)定值(理論平均值)為9,這個(gè)平均值的大小可以反映甲運(yùn)動(dòng)員的射箭水平.同理,乙射中環(huán)數(shù)的平均值為7×0.15+8×0.25+9×0.4+10×0.2=8.65.

  • 直線的一般式方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    直線的一般式方程教學(xué)設(shè)計(jì)人教A版高中數(shù)學(xué)選擇性必修第一冊(cè)

    解析:當(dāng)a0時(shí),直線ax-by=1在x軸上的截距1/a0,在y軸上的截距-1/a>0.只有B滿足.故選B.答案:B 3.過(guò)點(diǎn)(1,0)且與直線x-2y-2=0平行的直線方程是( ) A.x-2y-1=0 B.x-2y+1=0C.2x+y=2=0 D.x+2y-1=0答案A 解析:設(shè)所求直線方程為x-2y+c=0,把點(diǎn)(1,0)代入可求得c=-1.所以所求直線方程為x-2y-1=0.故選A.4.已知兩條直線y=ax-2和3x-(a+2)y+1=0互相平行,則a=________.答案:1或-3 解析:依題意得:a(a+2)=3×1,解得a=1或a=-3.5.若方程(m2-3m+2)x+(m-2)y-2m+5=0表示直線.(1)求實(shí)數(shù)m的范圍;(2)若該直線的斜率k=1,求實(shí)數(shù)m的值.解析: (1)由m2-3m+2=0,m-2=0,解得m=2,若方程表示直線,則m2-3m+2與m-2不能同時(shí)為0,故m≠2.(2)由-?m2-3m+2?m-2=1,解得m=0.

  • 人教版高中數(shù)學(xué)選擇性必修二等差數(shù)列的前n項(xiàng)和公式(2)教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選擇性必修二等差數(shù)列的前n項(xiàng)和公式(2)教學(xué)設(shè)計(jì)

    課前小測(cè)1.思考辨析(1)若Sn為等差數(shù)列{an}的前n項(xiàng)和,則數(shù)列Snn也是等差數(shù)列.( )(2)若a1>0,d<0,則等差數(shù)列中所有正項(xiàng)之和最大.( )(3)在等差數(shù)列中,Sn是其前n項(xiàng)和,則有S2n-1=(2n-1)an.( )[答案] (1)√ (2)√ (3)√2.在項(xiàng)數(shù)為2n+1的等差數(shù)列中,所有奇數(shù)項(xiàng)的和為165,所有偶數(shù)項(xiàng)的和為150,則n等于( )A.9 B.10 C.11 D.12B [∵S奇S偶=n+1n,∴165150=n+1n.∴n=10.故選B項(xiàng).]3.等差數(shù)列{an}中,S2=4,S4=9,則S6=________.15 [由S2,S4-S2,S6-S4成等差數(shù)列得2(S4-S2)=S2+(S6-S4)解得S6=15.]4.已知數(shù)列{an}的通項(xiàng)公式是an=2n-48,則Sn取得最小值時(shí),n為_(kāi)_______.23或24 [由an≤0即2n-48≤0得n≤24.∴所有負(fù)項(xiàng)的和最小,即n=23或24.]二、典例解析例8.某校新建一個(gè)報(bào)告廳,要求容納800個(gè)座位,報(bào)告廳共有20排座位,從第2排起后一排都比前一排多兩個(gè)座位. 問(wèn)第1排應(yīng)安排多少個(gè)座位?分析:將第1排到第20排的座位數(shù)依次排成一列,構(gòu)成數(shù)列{an} ,設(shè)數(shù)列{an} 的前n項(xiàng)和為S_n。

  • 人教版高中數(shù)學(xué)選擇性必修二函數(shù)的單調(diào)性(1)  教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選擇性必修二函數(shù)的單調(diào)性(1) 教學(xué)設(shè)計(jì)

    1.判斷正誤(正確的打“√”,錯(cuò)誤的打“×”)(1)函數(shù)f (x)在區(qū)間(a,b)上都有f ′(x)<0,則函數(shù)f (x)在這個(gè)區(qū)間上單調(diào)遞減. ( )(2)函數(shù)在某一點(diǎn)的導(dǎo)數(shù)越大,函數(shù)在該點(diǎn)處的切線越“陡峭”. ( )(3)函數(shù)在某個(gè)區(qū)間上變化越快,函數(shù)在這個(gè)區(qū)間上導(dǎo)數(shù)的絕對(duì)值越大.( )(4)判斷函數(shù)單調(diào)性時(shí),在區(qū)間內(nèi)的個(gè)別點(diǎn)f ′(x)=0,不影響函數(shù)在此區(qū)間的單調(diào)性.( )[解析] (1)√ 函數(shù)f (x)在區(qū)間(a,b)上都有f ′(x)<0,所以函數(shù)f (x)在這個(gè)區(qū)間上單調(diào)遞減,故正確.(2)× 切線的“陡峭”程度與|f ′(x)|的大小有關(guān),故錯(cuò)誤.(3)√ 函數(shù)在某個(gè)區(qū)間上變化的快慢,和函數(shù)導(dǎo)數(shù)的絕對(duì)值大小一致.(4)√ 若f ′(x)≥0(≤0),則函數(shù)f (x)在區(qū)間內(nèi)單調(diào)遞增(減),故f ′(x)=0不影響函數(shù)單調(diào)性.[答案] (1)√ (2)× (3)√ (4)√例1. 利用導(dǎo)數(shù)判斷下列函數(shù)的單調(diào)性:(1)f(x)=x^3+3x; (2) f(x)=sinx-x,x∈(0,π); (3)f(x)=(x-1)/x解: (1) 因?yàn)閒(x)=x^3+3x, 所以f^' (x)=〖3x〗^2+3=3(x^2+1)>0所以f(x)=x^3+3x ,函數(shù)在R上單調(diào)遞增,如圖(1)所示

  • 人教版高中數(shù)學(xué)選修3分類變量與列聯(lián)表教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選修3分類變量與列聯(lián)表教學(xué)設(shè)計(jì)

    一、 問(wèn)題導(dǎo)學(xué)前面兩節(jié)所討論的變量,如人的身高、樹(shù)的胸徑、樹(shù)的高度、短跑100m世界紀(jì)錄和創(chuàng)紀(jì)錄的時(shí)間等,都是數(shù)值變量,數(shù)值變量的取值為實(shí)數(shù).其大小和運(yùn)算都有實(shí)際含義.在現(xiàn)實(shí)生活中,人們經(jīng)常需要回答一定范圍內(nèi)的兩種現(xiàn)象或性質(zhì)之間是否存在關(guān)聯(lián)性或相互影響的問(wèn)題.例如,就讀不同學(xué)校是否對(duì)學(xué)生的成績(jī)有影響,不同班級(jí)學(xué)生用于體育鍛煉的時(shí)間是否有差別,吸煙是否會(huì)增加患肺癌的風(fēng)險(xiǎn),等等,本節(jié)將要學(xué)習(xí)的獨(dú)立性檢驗(yàn)方法為我們提供了解決這類問(wèn)題的方案。在討論上述問(wèn)題時(shí),為了表述方便,我們經(jīng)常會(huì)使用一種特殊的隨機(jī)變量,以區(qū)別不同的現(xiàn)象或性質(zhì),這類隨機(jī)變量稱為分類變量.分類變量的取值可以用實(shí)數(shù)表示,例如,學(xué)生所在的班級(jí)可以用1,2,3等表示,男性、女性可以用1,0表示,等等.在很多時(shí)候,這些數(shù)值只作為編號(hào)使用,并沒(méi)有通常的大小和運(yùn)算意義,本節(jié)我們主要討論取值于{0,1}的分類變量的關(guān)聯(lián)性問(wèn)題.

  • 人教版高中數(shù)學(xué)選修3二項(xiàng)式系數(shù)的性質(zhì)教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選修3二項(xiàng)式系數(shù)的性質(zhì)教學(xué)設(shè)計(jì)

    1.對(duì)稱性與首末兩端“等距離”的兩個(gè)二項(xiàng)式系數(shù)相等,即C_n^m=C_n^(n"-" m).2.增減性與最大值 當(dāng)k(n+1)/2時(shí),C_n^k隨k的增加而減小.當(dāng)n是偶數(shù)時(shí),中間的一項(xiàng)C_n^(n/2)取得最大值;當(dāng)n是奇數(shù)時(shí),中間的兩項(xiàng)C_n^((n"-" 1)/2) 與C_n^((n+1)/2)相等,且同時(shí)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.各二項(xiàng)式系數(shù)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 的展開(kāi)式的各二項(xiàng)式系數(shù)之和為2^n1. 在(a+b)8的展開(kāi)式中,二項(xiàng)式系數(shù)最大的項(xiàng)為 ,在(a+b)9的展開(kāi)式中,二項(xiàng)式系數(shù)最大的項(xiàng)為 . 解析:因?yàn)?a+b)8的展開(kāi)式中有9項(xiàng),所以中間一項(xiàng)的二項(xiàng)式系數(shù)最大,該項(xiàng)為C_8^4a4b4=70a4b4.因?yàn)?a+b)9的展開(kāi)式中有10項(xiàng),所以中間兩項(xiàng)的二項(xiàng)式系數(shù)最大,這兩項(xiàng)分別為C_9^4a5b4=126a5b4,C_9^5a4b5=126a4b5.答案:1.70a4b4 126a5b4與126a4b5 2. A=C_n^0+C_n^2+C_n^4+…與B=C_n^1+C_n^3+C_n^5+…的大小關(guān)系是( )A.A>B B.A=B C.A<B D.不確定 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

  • 人教版高中數(shù)學(xué)選修3一元線性回歸模型及其應(yīng)用教學(xué)設(shè)計(jì)

    人教版高中數(shù)學(xué)選修3一元線性回歸模型及其應(yīng)用教學(xué)設(shè)計(jì)

    1.確定研究對(duì)象,明確哪個(gè)是解釋變量,哪個(gè)是響應(yīng)變量;2.由經(jīng)驗(yàn)確定非線性經(jīng)驗(yàn)回歸方程的模型;3.通過(guò)變換,將非線性經(jīng)驗(yàn)回歸模型轉(zhuǎn)化為線性經(jīng)驗(yàn)回歸模型;4.按照公式計(jì)算經(jīng)驗(yàn)回歸方程中的參數(shù),得到經(jīng)驗(yàn)回歸方程;5.消去新元,得到非線性經(jīng)驗(yàn)回歸方程;6.得出結(jié)果后分析殘差圖是否有異常 .跟蹤訓(xùn)練1.一只藥用昆蟲(chóng)的產(chǎn)卵數(shù)y與一定范圍內(nèi)的溫度x有關(guān),現(xiàn)收集了6組觀測(cè)數(shù)據(jù)列于表中: 經(jīng)計(jì)算得: 線性回歸殘差的平方和: ∑_(i=1)^6?〖(y_i-(y_i ) ?)〗^2=236,64,e^8.0605≈3167.其中 分別為觀測(cè)數(shù)據(jù)中的溫度和產(chǎn)卵數(shù),i=1,2,3,4,5,6.(1)若用線性回歸模型擬合,求y關(guān)于x的回歸方程 (精確到0.1);(2)若用非線性回歸模型擬合,求得y關(guān)于x回歸方程為 且相關(guān)指數(shù)R2=0.9522. ①試與(1)中的線性回歸模型相比較,用R2說(shuō)明哪種模型的擬合效果更好 ?②用擬合效果好的模型預(yù)測(cè)溫度為35℃時(shí)該種藥用昆蟲(chóng)的產(chǎn)卵數(shù).(結(jié)果取整數(shù)).

  • 新人教版高中英語(yǔ)選修2Unit 4 Journey Across a Vast Land教學(xué)設(shè)計(jì)

    新人教版高中英語(yǔ)選修2Unit 4 Journey Across a Vast Land教學(xué)設(shè)計(jì)

    當(dāng)孩子們由父母陪同時(shí),他們才被允許進(jìn)入這個(gè)運(yùn)動(dòng)場(chǎng)。3.過(guò)去分詞(短語(yǔ))作狀語(yǔ)時(shí)的幾種特殊情況(1)過(guò)去分詞(短語(yǔ))在句中作時(shí)間、條件、原因、讓步狀語(yǔ)時(shí),相當(dāng)于對(duì)應(yīng)的時(shí)間、條件、原因及讓步狀語(yǔ)從句。Seen from the top of the mountain (=When it is seen from the top of the mountain), the whole town looks more beautiful.從山頂上看,整個(gè)城市看起來(lái)更美了。Given ten more minutes (=If we are given ten more minutes), we will finish the work perfectly.如果多給十分鐘,我們會(huì)完美地完成這項(xiàng)工作。Greatly touched by his words (=Because she was greatly touched by his words), she was full of tears.由于被他的話深深地感動(dòng),她滿眼淚花。Warned of the storm (=Though they were warned of the storm), the farmers were still working on the farm.盡管被警告了風(fēng)暴的到來(lái),但農(nóng)民們?nèi)栽谵r(nóng)場(chǎng)干活。(2)過(guò)去分詞(短語(yǔ))在句中作伴隨、方式等狀語(yǔ)時(shí),可改為句子的并列謂語(yǔ)或改為并列分句。The teacher came into the room, followed by two students (=and was followed by two students).后面跟著兩個(gè)學(xué)生,老師走進(jìn)了房間。He spent the whole afternoon, accompanied by his mom(=and was accompanied by his mom).他由母親陪著度過(guò)了一整個(gè)下午。

  • 新人教版高中英語(yǔ)選修2Unit 1 Science and Scientists-Using langauge教學(xué)設(shè)計(jì)

    新人教版高中英語(yǔ)選修2Unit 1 Science and Scientists-Using langauge教學(xué)設(shè)計(jì)

    This happens because the dish soap molecules have a strong negative charge, and the milk molecules have a strong positive charge. Like magnets, these molecules are attracted to each other, and so they appear to move around on the plate, taking the food coloring with them, making it look like the colors are quickly moving to escape from the soap.Listening text:? Judy: Oh, I'm so sorry that you were ill and couldn't come with us on our field trip. How are you feeling now? Better?? Bill: Much better, thanks. But how was it?? Judy: Wonderful! I especially liked an area of the museum called Light Games.it was really cool. They had a hall of mirrors where I could see myself reflected thousands of times!? Bill: A hall of mirrors can be a lot of fun. What else did they have?? Judy: Well, they had an experiment where we looked at a blue screen for a while, and then suddenly we could see tiny bright lights moving around on it. You'll never guess what those bright lights were!? Bill: Come on, tell me!? Judy: They were our own blood cells. For some reason, our eyes play tricks on us when we look at a blue screen, and we can see our own blood cells moving around like little lights! But there was another thing I liked better. I stood in front of a white light, and it cast different shadows of me in every color of the rainbow!? Bill: Oh, I wish I had been there. Tell me more!? Judy: Well, they had another area for sound. They had a giant piano keyboard that you could use your feet to play. But then, instead of playing the sounds of a piano, it played the voices of classical singers! Then they had a giant dish, and when you spoke into it, it reflected the sound back and made it louder. You could use it to speak in a whisper to someone 17 meters away.? Bill: It all sounds so cool. I wish I could have gone with you? Judy: I know, but we can go together this weekend. I'd love to go there again!? Bill: That sounds like a great idea!

  • 新人教版高中英語(yǔ)選修2Unit 2 Bridging Cultures-Discovering useful structures教學(xué)設(shè)計(jì)

    新人教版高中英語(yǔ)選修2Unit 2 Bridging Cultures-Discovering useful structures教學(xué)設(shè)計(jì)

    The grammar of this unit is designed to review noun clauses. Sentences that use nouns in a sentence are called noun clauses. Nominal clauses can act as subject, object, predicate, appositive and other components in compound sentences. According to the above-mentioned different grammatical functions, nominal clauses are divided into subject clause, object clause, predicate clause and appositive clause. In this unit, we will review the three kinds of nominal clauses. Appositive clauses are not required to be mastered in the optional compulsory stage, so they are not involved.1. Guide the students to judge the compound sentences and determine the composition of the clauses in the sentence.2. Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.3. Inspire the students to systematize the function and usage of noun clause1.Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.2.Inspire the students to systematize the function and usage of noun clauseStep1: The teacher ask studetns to find out more nominal clauses from the reading passage and udnerline the nominal clauses.

  • 新人教版高中英語(yǔ)選修2Unit 3 Food and Culture-Discovering useful structures教學(xué)設(shè)計(jì)

    新人教版高中英語(yǔ)選修2Unit 3 Food and Culture-Discovering useful structures教學(xué)設(shè)計(jì)

    The newspaper reported more than 100 people had been killed in the thunderstorm.報(bào)紙報(bào)道說(shuō)有一百多人在暴風(fēng)雨中喪生。(2)before、when、by the time、until、after、once等引導(dǎo)的時(shí)間狀語(yǔ)從句的謂語(yǔ)是一般過(guò)去時(shí),以及by、before后面接過(guò)去的時(shí)間時(shí),主句動(dòng)作發(fā)生在從句的動(dòng)作或過(guò)去的時(shí)間之前且表示被動(dòng)時(shí),要用過(guò)去完成時(shí)的被動(dòng)語(yǔ)態(tài)。By the time my brother was 10, he had been sent to Italy.我弟弟10歲前就已經(jīng)被送到意大利了。Tons of rice had been produced by the end of last month. 到上月底已生產(chǎn)了好幾噸大米。(3) It was the first/second/last ... time that ...句中that引導(dǎo)的定語(yǔ)從句中,主語(yǔ)與謂語(yǔ)構(gòu)成被動(dòng)關(guān)系時(shí),要用過(guò)去完成時(shí)的被動(dòng)語(yǔ)態(tài)。It was the first time that I had seen the night fact to face in one and a half years. 這是我一年半以來(lái)第一次親眼目睹夜晚的景色。(4)在虛擬語(yǔ)氣中,條件句表示與過(guò)去事實(shí)相反,且主語(yǔ)與謂語(yǔ)構(gòu)成被動(dòng)關(guān)系時(shí),要用過(guò)去完成時(shí)的被動(dòng)語(yǔ)態(tài)。If I had been instructed by him earlier, I would have finished the task.如果我早一點(diǎn)得到他的指示,我早就完成這項(xiàng)任務(wù)了。If I had hurried, I wouldn't have missed the train.如果我快點(diǎn)的話,我就不會(huì)誤了火車。If you had been at the party, you would have met him. 如果你去了晚會(huì),你就會(huì)見(jiàn)到他的。

  • 新人教版高中英語(yǔ)選修2Unit 3 Food and Culture-Reading and thinking教學(xué)設(shè)計(jì)

    新人教版高中英語(yǔ)選修2Unit 3 Food and Culture-Reading and thinking教學(xué)設(shè)計(jì)

    The discourse explores the link between food and culture from a foreign’s perspective and it records some authentic Chinese food and illustrates the cultural meaning, gerography features and historic tradition that the food reflects. It is aimed to lead students to understand and think about the connection between food and culture. While teaching, the teacher should instruct students to find out the writing order and the writer’s experieces and feelings towards Chinese food and culture.1.Guide the students to read the text, sort out the information and dig out the topic.2.Understand the cultural connotation, regional characteristics and historical tradition of Chinese cuisine3.Understand and explore the relationship between food and people's personality4.Guide the students to use the cohesive words in the text5.Lead students to accurately grasp the real meaning of the information and improve the overall understanding ability by understanding the implied meaning behind the text.1. Enable the Ss to understand the structure and the writing style of the passage well.2. Lead the Ss to understand and think further about the connection between food and geography and local character traits.Step1: Prediction before reading. Before you read, look at the title, and the picture. What do you think this article is about?keys:It is about various culture and cuisine about a place or some countries.

  • 新人教版高中英語(yǔ)選修2Unit 5 First Aid-Discovering useful structures教學(xué)設(shè)計(jì)

    新人教版高中英語(yǔ)選修2Unit 5 First Aid-Discovering useful structures教學(xué)設(shè)計(jì)

    You have no excuse for not going.你沒(méi)有理由不去。He was punished for not having finished his homework.他因未完成作業(yè)而受到懲罰。2.動(dòng)詞­ing形式復(fù)合結(jié)構(gòu)由物主代詞或人稱代詞賓格、名詞所有格或普通格加動(dòng)詞­ing,即“sb./sb.'s+doing”構(gòu)成。動(dòng)詞­ing形式的復(fù)合結(jié)構(gòu)實(shí)際上是給動(dòng)詞­ing形式加了一個(gè)邏輯主語(yǔ)。動(dòng)詞­ing形式的復(fù)合結(jié)構(gòu)有四種形式:①形容詞性物主代詞+動(dòng)詞­ing②名詞所有格+動(dòng)詞­ing③代詞賓格+動(dòng)詞­ing④名詞+動(dòng)詞­ingHer coming to help encouraged all of us.她來(lái)幫忙鼓舞了我們所有人。The baby was made awake by the door suddenly shutting.這個(gè)嬰兒被突然的關(guān)門聲吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做飯的樣子嗎?無(wú)生命名詞無(wú)論是作主語(yǔ)還是作賓語(yǔ)都不能用第②種形式。Tom's winning first prize last year impressed me a lot.湯姆去年得了一等獎(jiǎng)使我印象深刻。Do you mind my/me/Jack's/Jack leaving now?你介意我/杰克現(xiàn)在離開(kāi)嗎?Excuse me for my not coming on time.很抱歉我沒(méi)能按時(shí)來(lái)。His father's being ill made him worried.他父親病了,他很擔(dān)心。We are looking forward to the singer's/the singer to give us a concert.我們盼望著這位歌手來(lái)給我們舉辦一場(chǎng)演唱會(huì)。

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