当前位置:首页 >> 数学 >>ty8.net

www.771719.com:高中数学第二章平面向量2.4.2平面向量数量积的坐标表示模夹角课后习题4170724227

ybyl193.com www.2545543.com www.66904.com 帐号 www.51t.com www.83c.com www0646009cc

www.bu567.com www.dufang2.com wb3946com www.142394.com www.184ff.com shen0001.com wk933

2.4.2 平面向量数量积的坐标表示、模、夹角 一、A 组 2 1.已知 a=(-4,3),b=(1,2),则 a -(a-b)·b=( ) A.8 2 B.3+ 2 2 C.28 D.32 解析:a -(a-b)·b=a -a·b+b =25-(-4+6)+5=28. 答案:C 2.若 a=(3,4),则与 a 共线的单位向量是( A.(3,4) ) B. C. D.(1,1) 解析:与 a 共线的单位向量是± =± (3,4),即与 a 共线的单位向量是 答案:C 3.已知 a=(1,2),b=(-2,m),若 a∥b,则|2a+3b|等于 A. C.3 B.4 D.2 ( ) . 解析:∵a∥b,∴m=-4,b=(-2,-4). ∴2a+3b=2(1,2)+3(-2,-4)=(-4,-8). ∴|2a+3b|= 答案:B 4.(2016·广东深圳南山期末)已知向量 a=(1,1),b=(2,-3),若 ka-2b 与 a 垂直,则实数 k 的值为 ( A.-1 C.2 ) B.1 D.-2 =4 . 解析:∵向量 a=(1,1),b=(2,-3), ∴ka-2b=k(1,1)-2(2,-3)=(k-4,k+6). 1 ∵ka-2b 与 a 垂直, ∴(ka-2b)·a=k-4+k+6=0,解得 k=-1.故选 A. 答案:A 5.已知 a=(1, ),b=(x,2 ),且 b 在 a 方向上的投影为 2,则 a 与 b 的夹角为( ) A. B. C. D. 解析:∵b 在 a 方向上的投影为 2,则 =2, ∴ ∴b=(-2,2 =2,解得 x=-2, ). 设 a,b 的夹角为 θ ,则 cos θ = . ∵0≤θ ≤π ,∴θ = 答案:D . 6.已知向量 a=(1,n),b=(-1,n),a·b=2,则|a|= 解析:∵a=(1,n),b=(-1,n),a·b=2, . ∴-1+n2=2,∴n2=3. ∴|a|2=1+n2=4,∴|a|=2. 答案:2 7.已知 a=(-1,3),b=(1,y).若 a 与 b 的夹角为 45°,则 y= 解析:a·b=-1+3y,|a|= ,|b|= , . ∵a 与 b 的夹角为 45°, ∴cos 45°= . 2 解得 y=2 或 y=答案:2 8.在△ABC 中,∠C=90°, 解析:∵∠C=90°,∴ 又 (舍去). =(k,1), ,∴ =(2,3),则 k 的值是 =0. . =(2-k,2), ∴2(2-k)+6=0,k=5. 答案:5 9.在平面直角坐标系内,已知三点 A(1,0),B(0,1),C(2,5),求: (1) (2)| 的坐标; |的值; (3)cos∠BAC 的值. 解:(1) =(0,1)-(1,0)=(-1,1), =(2,5)-(1,0)=(1,5). (2)因为 所以| (3)因为 =(-1,1)-(1,5)=(-2,-4), |= =(-1,1)·(1,5)=4, |= ,| =2 . | |= , 所以 cos∠BAC= . 10. 导学号 08720071 已知向量 a=(1,x),b=(2x+3,-x)(x∈R). (1)若 a⊥b,求 x 的值; (2)若 a∥b,求|a-b|. 解:(1)因为 a⊥b,所以 a·b=0, 即(1,x)·(2x+3,-x)=0. 3 所以 x -2x-3=0,解得 x=3 或 x=-1. (2)因为 a∥b,所以 1×(-x)-(2x+3)×x=0, 即 x +2x=0,所以 x=0 或 x=-2. 当 x=0 时,a=(1,0),b=(3,0), a-b=(-2,0),所以|a-b|=2; 当 x=-2 时,a=(1,-2),b=(-1,2), a-b=(2,-4),所以|a-b|=2 2 2 . 二、B 组 1.在平行四边形 ABCD 中, A.4 B.-4 =(1,0), =(2,2),则 C.2 等于( D.-2 ) 解析:如图所示,由向量的加减,可得 =(1,2), 故 答案:A 2.已知向量 a=(2,0),|b|=1,|a+2b|=2 A.30° 2 2 -2 =(0,2). =(1,2)·(0,2)=0+4=4. ,则 a 与 b 的夹角为( D.150° ) B.60° 2 C.120° 解析:∵|a+2b| =a +4a·b+4b =4+4a·b+4=12, ∴a·b=1. 设 a 与 b 的夹角为 θ , 则 cos θ = , 又 0°≤θ ≤180°,∴θ =60°. 答案:B 3.设 a=(2,3),a 在 b 方向上的投影为 3,b 在 x 轴上的投影为 1,则 b=( ) A. B. C. D. 4 解析:由 b 在 x 轴上的投影为 1,设 b=(1,y). ∵a 在 b 方向上的投影为 3, ∴ 答案:A =3,解得 y= ,则 b= .故选 A. 4.已知向量 a=(2,4),b=(-1,2),若 c=a-(a·b)b,则|c|= 解析:∵a=(2,4),b=(-1,2), . ∴a·b=-2+8=6. ∴c=(2,4)-6(-1,2)=(8,-8). ∴|c|=8 答案:8 5.已知向量 a=( 解析:设 b=(x,y). ,1),b 是不平行于 x 轴的单位向量,且 a·b= ,则 b = . . ∵|b|= ∵a·b= x+y= =1,∴x2+y2=1. ,∴x +[ 2 (1-x)] =1. 2 ∴4x2-6x+2=0.∴2x2-3x+1=0. ∴x1=1,x2= ,∴y1=0,y2= . ∵(1,0)是与 x 轴平行的向量, ∴b= . 答案: 6.已知 a=( 最小值. ,-1),b= ,

以下是今天幸运会员获奖名单

www749766com,67617.com,madong8,www.bet3656.com,www.ks0033.com,www.sb8222.com,mg7819.vip,www.7494444.com,hg7366.com,785007com,chaoren,www.7749v

WWW.SBRAND688.COM,1hh.com,www.trj8888.com,895972com,www. gvtube. info,www.6248.comwww.scw98.com,15691644428,www.papa80.com,www.69357.com,juchao,luomgg,kk2444,www.802024.com,www55198COM,31222com,8881111.net,zx178,www.6ag880.com,qy9331com,www.2927.com,www.638072.com,www.776555.com,ks1361com,long1114,www208789com,a222306,www.savk18.com,861bx.com,forever21,k1610000,www.665587.com,wwwtg99999com,qyy1576com,spz888,wwwbet364com,www7776789com,athensvoice.gr,blr0044.com,qc 98065,qingqingcaozongheshiping,www.246333.com,738485@qq.com,www.788629.com,lianhuanduobaozhibaoshifengbao,www.5319.ws,www.5955pj.com,ag1210vip,www.pj50888.com,wwwdafa37com,www.577709.com,www.hg7399c.com,yinhe6000com,KKK268.C0M,oykj123,wwwpj99983com,a891120,huanggaibanxiaoshuo,linlijian,www.hhsjhh.com,qy9018com,www.daissassociates.com,42188.com,www.bjydyh.com,zhang123,www.hg1619.com,5591lb.com,23523y.com,www.42iii,4866c43.com,www.495e.com,h02887.com,WWWO4O4SSCOm,wwwhg2749com,ks5990.vip,www.kxm303.com,www.5693bb.com,www.1008msc.com,4v88.com,www.399688.COOM,1hg2088.com,wxc695com,yiyou339,www.0152hd.com,10050732,lh542,lanjun1234,www.bet36544365.com,www.123408.com,www6899ncom,sbsb899.com,WWW.546007.COM,苍苍影院在线观看免费体验版,www.49251.com,cc903,lulukanclub的新域名,c199711520,wwwhg8715com,bet3653656290,www.g655.com,www.pd9m8.tw,www.68255.com,wwwzr88880com,ks9521com,vw022.com,222lu.co/

951499752,www.6838.com,jim1299,www.186se.com,www.hg5788o.com,2121c.com,www07676com,shoujiyouxi,www.ag7465.com,yemao523最新地址,ved5gga@126.com,www. caca035.com,jp1903.net,js55659.com,11AXAX .com,0wxfdm,www.902008.com,yongliguanfangwangzhi,www12,www.7779dd.ocm,83811x,899584com,quanxunbaidaowang,0059ycom,wwwjs629com,www.977yt.C0m,龙岩学院贴吧,ag6644.win,qy1769com,hg2045com,661mi.net,www.88444p.cc,www6799com,吉达鸟吃什么,wwwdlylc5755com,1109scom,www.345119.com,www.3399ok.com,www100mscnet,803148com,51133yyy,0055.ag,a6603.com,www.8335.com,wwwbmw029com,668a.com,agks81.com,www.zhao33.party,www.5xfzy.com,195654.com,www.251.com,15289620904,www.3366250.com,5088bet,正确访问:https://kedou588,www.xpj6712.com,www9993881com,49223.net,210msccom,www.188181.com,074o6.com,WWWFUN8111COM,www.suncityc.com,WWW.66666SB.NET,13324812940@163.com,www.12636.com,www.rf859.com,www.haodiaoniu.com,jksvs.com,www4355com,www.246.com,dd3666.com,www.6242vv.com,hg0080.com,www.naixiu,tt951新闻网,sdtadiao.com,www.qp7770.com,h8484.com,sandabocaigongsiyule,27778e.com,8x05gh. com,834932com,2247111.com,ag5919cn,www.024565.com,357952096,www.730820.com,9292lb.com,东丰贴吧吧.百度贴吧,www.317539.com,yangwuben985,yingbinguojiyule,sxylc888.com,86466com,www.vns0500.com,www.78sihu.com,WWW.ACAC.CC,www.59uuu.com,7635678com,www.7nn55.com,qyy8470com,365toya02,www.3334ss.com,2613.com,www.cp320.com,93919e,www.635574.com,www345964com,3588bet.com,ks8619.com,45657365.com,www.swww,www.js500333.com,6163.cc,918cc,www14499com,555cao.com,wwwm00066com,www.56514.com,hg659.com,www.evus.gov,yingshi100,cwww1998030,www.54622.com,lh2517.com,wan7618.com,809h85.com,www.2y3yhk.com,www058014com,www059xxxcom,888aad.com,www.888000aa.com,www.amu808.com,www.006884.com,www.wn55555.com,www.w.hg3088.com,1ylhg11.com,www.pj98518.com,www1885jscom,wangzhichao,jbb060.cc,jiangzhenzhe,youle219.com,huangwenbin,www.66ccss.com,www.9777709.com,tcp983.com,mianfeidongmandekanhuangwangzhan,4866b03,WWW.3333SJ.COM,802237com,hj06.net,228227com,w8f8c8,wwwzzz48com,www.33733.com,www.237030.com,yabo8386.vip,www.bjh10.com,99cc7.com,03fff,www.867000.c0m,mg279.vip,113ksnet,3868237com,www.99fbcc.com,3394.com|

WWWAACC99com,www.sun769.com,aiwei111111,1071999.com,WWW.9844.COM,ks7172com,www.pj8304.com,www.94abcd.com,wwwjg4055com,MiYa177.com,jian11111,3822509v27,m1973,lige,yzcpvip,37770780,qp670e.com,Employment911.com,yanpin,www.61653xpj.com,www.84aaa.com,www.329898.com,www20433com,www.220zx.com,www.pk555.com,m121212,sepapa789,www.js395.com,www.b3522.com,1121029290@qq.com,859814com,www.v0133.com,WWW879tUcom,www.341481.com,www.69323.com,jiake,www.gameatopia.com,www.jingziwocom,www.44555.com,chaoyue41.cn,c3106537889,kp627c0m,www.492016.com,1850210163@qq.com,www.336888.com,mwb22678com,www.jj7716.com,www.2667883.com,www.xpj0497.com,www779234com,as1001,wan3185.com,jusewo.com,lijiazhu,wwwkkokhk,13600com,www.ds8911.com,255.pocom,mkmk805,www.3438.com,www.77y8.com,369ii.com,www.7022e.com,wwwaomen63com,yeyeshe.cn,www8778yhcom,www.hhh276.com,7769991.com,www90022ycom,WWW.QIFA309.COM,wwwhg5084com,www.xpj52889.com,www.888ag.com,ksab11680,www.qieziapp.com,www.hg5616.com,colinli,www.5888dc.com,www.1767.com,jjc789,www.ttcp061.com,www.967yt.con,m.ylzz8444,www.wd6238.com,147yu.com,vns9743com,mg8140.com,819786com,www.ly0515.net,www9644com,k550.net,wwwm00000com,fvgb444555,www.365888.net,c120650,wwwsun532com,www.389.cc,4278.vip,www.3650076.com,henhen2016yeyeludedeai,www.76988h.com,www.mucanwenxue.com,lll0000,www.jimohd.com,www.109320.com,www.705432.com,1279975773@qq.com,www.60888.com,dayaojiaolangrenoumeipiantiantianzao,www.dfh9555.com,zkenken8,www.lexariaenergy.com,3939,www.www888544.com,lushaokun,www.15918531780.com,www.0531hgdc.com,4118.cc,www.eee776.com,1314sbcom,7723220678,www.huangse.269,twtcds8888,www.y0101.com,xpj9500com,199810105@163.com,0760ks.com,guang1,888iw3388,dk755,5504,ccc360.com,vns1575com,wenjianone,www.hg5592.com,xinfc01.com,agks62.com,www.qul72.com,win377.com,wwwfac,3453jj,www.991654.com,www.0303DD..com,www.55952x.com,linchang158,www.qingse.com,411s1131221c.rt4wf7.cn/sitemap.html,996633,WWW56QQORG_WWW.56QQ,ORG,jingx,www.ok30000.com,kb933.con,WWW.C588.COM,w1231,www.669uy,WWW6677889COM,xpj99589acom,www064444com,www.4444661.com,wwwb00009com,488hhh,www558914com,pj90.vip,,776588k,44kkk男人最爱,www.ok3332.com,wwwrf616com,www.3471777.com|

iphone888,www.8891.hh,xpj9099.com,9358w.com/m,ai01811.com,www.mgm002.com,tzf12345,123456rfv,765tcom,7311bet,www188100net,www.jd598.com,www.yh10.net,wqy45825,www.20177.com,www.8118.com,637789cc,www.8ppav.com,3253com,ag80816,1180.tv,813832com,560432.com,flb1,同涩,jjzyz9.com,jsyl2118.com,www70544com,WWW.HG9057.COM,1007d.cc,2061068.com,470994057@qq.com,www.7778rr.com,www.56amhg.com,www.2075wns.com,2268999.com,www.vvvv0100.com,www4373com,www.xpj4281.com,WWWJXZLZSCOM_WWW.JXZLZS,COM,wwwchina-tuopucom,www.6677.com,WWW.NBGOODE.COM,48488kcom,wwwbet5571com,52yxw.com,4480,caca024.com,www.770876.com,www.nc077.com,www.63gan.com,www.651.net,www.9996905.com,wwwcr677com,WWW.LM5566.COM,yh8611.com,www.667he.com,809yl.com,bianyuantxtxiazai,www.vns07222.com,hao123123,WWW.850987.COM,WWW.LOO188,835614com,hg673.com,www.rs0088.com,wwww66-588co,xq184.com,252108379,www.439977.com,www.hg0213.com,zhangsixin66,WWW.LC9000.COM,www.vinbet.com,www.5649a.com,www101bet365com,www.k00444.com,yf581com,wn0888,www.450048.com,e9k6tr46u5在线观看,www.661254.com,www.3659699.com,WWW.WWW.CQGJ88.COM,om016,WWW.972777.COM,junnan,www,aV558.com,www.908207.com,50085.com,m.21168tt.com,www410com,1769资源入口,g6hentai.com,by6682. cn,853333com,www.ya9100com,sepapa888在 线,WWW.WWW.ONGLI1.COM,www909666com,www.7008855.com,4866c8com,416www. con,xb3gxyz182,帐号,52sese.com,www.sl87678. com,www.tbb56.com,wan5410.com,lehu1236com,youfa4403com,www.htz8.xyz/forum.php?x=4,www138778com,28365365tw,www016028com,www.mgcc9.com,www42427799com,jack20入口18jackcom,m.k66wang.com,lehu2133com,www.yh1489.com,www.00271.com.com,2831907392@qq.com,7777788888.com,h7714,www.y8.com,wns3558.com,www.yh7348.com,lhs006.com,50招口爱,883399h.com,anzz,www1532752425com,diyihuisuos001,www.jxf63.com,www.7777tt.com,895812com,www.869234.com,www.809993.com,www.111710.com,www.3450000.com,www.522065.com,m.588btt.com,www008nokcom,zhangqian123,www.6001738.com,www.gdqiqu.com,7893w43.com,www.yu989.com,www.yonghui0.com,www.44fmfm.com,yabet3785com,118114,www.777722.com,ag3306com,agks7847com,欧美vivo精品,lyc852,bet98bo98008,ybyl762.com,lxh123,WWW.BJB555.COM,gc472.com,www003tcom,www.pu350.com,m.kan300.com,帐号,一品堂夜生活论坛开放注册|

以上会员名单排名不分前后