【“guomubuwang(tiyanban)”yiqidong,chixushijian:59fen59miao。】
binglengerjingzhundedaojishisheng,rutongzhangubanzaiqinfengdenaohaizhongleixiang。
neiyishunjian,qinfengganjuezijidedanaofangfobeiyidaowuxingdedianliuchuanguo,zhenggeshijiezaitadeganzhizhongshunjianbiandebutong!
yanqiandekezhuo,muwendemeiyisixiweizouxiangdouqingxiderutongdaoke;kongqizhongpiaofudeweichen,zaitouguochuanglingdeyangguangxia,qiyundongguijidoufangfobeifangmanlewushubei,lilizaimu。tadeerduonengbuzhuodaojiaoshiwaizoulangshangqitabanjilaoshijiangkedemohushengyin,shenzhinengfenbianchugebibanhuaxuelaoshineidutedeshayasangyin。
gengrangtagandaozhenhandeshitadesiwei。
ruguoshuozhiqiandenaodaishiyitailaojiudebentengdiannao,yunxinggesaoleidoukadun,neimexianzai,tajiuxiangshishunjianshengjichenglezuidingjiandeliangzijisuanji!siweideyunzhuansudu、qingxidu、yijiduixinxidebuzhuohechulinengli,doudadaoleyigetayiwangxiangdoubuganxiangdekongbujingdi!
“zheijiushi……guomubuwang?”qinfengnannanziyu,yanzhongshanshuozhenanyizhixindeguangmang。
tameiyousihaoyouyu,jihushibennengdi,yibazhuaguozhuomianshangneibenzhanxinde、jihumeizenmefandongguode《gaozhongshuxuebixiuwu》,yijipangbianduijirushande《wuniangaokaoxnianmoni》、《huangxmijuan》、《xuebabiji》denggezhongfuxiziliao。
zheixiecengjingzaitayanzhongrutongtianshuyibandecunzai,cike,quesanfazheqiansuoweiyoudexiyinli。
“shijianzhiyouyixiaoshi!”qinfengshenxiyikouqi,qiangyaxiaxinzhongdejidang,muguangruiliruyingsun。
tashouxianjiangneidaoxitongfabude、haocheng“gaokaoyazhoutijibie(lveyouchaogang)”defuzahanshuti,shenshendiluoyinzainaohaizhong。meiyigefuhao,meiyigejiaobiao,meiyigetiaojian,douzai“guomubuwang”dejiachixia,beiwanmeifuke,fenhaobucha。
jinjiezhe,tafankaile《gaozhongshuxuebixiuwu》。
“唰唰唰——”
shuyefandongdeshengyinzaianjingdejiaoluolixiandegewaiqingxi。
qinfengdemuguangrutongzuijingmidesaomiaoyi,feisudilveguoshuyeshangdemeiyigezi、meiyigegongshi、meiyigeliti。
neixiecengjingrangtatoutongyulie、baisibudeqijiededingyi、dingli、tuilun,cikerutongwenshundemianyangban,guaiguaidiyongrutadenaohai,bingqiebeixunsuguilei、zhengli、jiyi。
“yuanlaihanshudedandiaoxingshizheimepanduande……”
“daoshudejiheyiyi……zhiqianzenmejiumeilijietoucheni?”
“zheigeluobidafaze,shushangjingranyoutidao!suiranzhishizaituozhanyueduli……”
wushucengjingmohubuqing、huozhegancuijiumeikanjinqudezhishidian,zai“guomubuwang”dekongbuxiaoguoxia,beitayiyizhongcuikulaxiubandesuduqiangxingjiyibingchubulijie。
tadedanaoxiangyikuaiganhedehaimian,fengkuangdixishouzhezhishideganlin。
duanduanshifenzhong,yibenhouhoude《bixiuwu》hexinneirong,jingranbeitahuluntunzaoban“ken”lexialai!suiranhenduoshencengcideluojiguanliantaweibinenglikeronghuiguantong,danzhishao,suoyoudegongshi、dinglihejibenjietibuzhou,tadoujideyiqingerchu!
这种感觉,太爽了!
jianzhijiuxiangshiwuxiaxiaoshuolidezhujiaobeidatonglerenduermai,xueshenmedoushiyidianjiutong!
qinfengshenzhinengqingxidiganjuedao,suizhezhishideyongru,taneiganggangtishengdao7diandezhili,zhengzaibeiyouxiaodiliyongqilai,bangzhutaduizheixieqiangxingjiyixialaidexinxijinxingchubudexiaohuaheshuli。
tameiyoutingxie,jinjiezheyouzhuaqile《wuniangaokaoxnianmoni》zhongguanyuhanshuyudaoshudebufen。
hailiangdetixing,gezhongdiaozuandekaofa,wuhuabamendejietijiqiao……
ruoshicongqian,guangshikandaozheixiemimimamadetimu,qinfengkongpajiuyijingtoupifama,zhijiexuanzefangqile。
danxianzai,taquekandejinjinyouwei,shenzhiyouxieruchiruzui。
meiyidaoti,zaitayanzhongdouxiangshiyigedengdaibeijiekaidemiti。tafeisudiyuedutimu,ranhouduizhaodaanjiexi,jianggezhongjietisilu、guanjianbuzhou、yicuodian,yiyimingjizaixin。
“yuanlaizheidaotikeyiyonggouzaohanshudefangfa……”
“zheigecanshufenlifa,yongzaizheilizhenshiqiaomiao!”
“haiyouzheizhonghuanyuanjiqiao,woyiqianzenmejiumeixiangdao?”
tadeetoushangshenchuleximidehanzhu,bushiyinweilei,ershiyinweidanaogaosuyunzhuandailaidexingfen。tadeyanshenzhuanzhuermingliang,fangfoyouliangtuanhuoyanzairanshao。
shijianyifenyimiaodiliushi。
sishifenzhonghou,qinfengjihujiangshoutousuoyouyuhanshu、daoshu、budengshi、jiexijihexiangguandehexinzhishidianhedianxingtixing,douyong“guomubuwang”denengliqiangxing“sai”jinlenaozili。
tadedanaocikejiuxiangyigebeisaimanledingjishicaidechaojibingxiang,suiranhenduodongxihaimeilaideji“pengrenxiaohua”,danzhishao,“yuancailiao”yijingchubeidaoleyigejingrendedibu!
【“guomubuwang(tiyanban)”shengyushijian:19fen37miao。】
xitongdetishiyinshishixiangqi。
“shijianbuduole,gaijiejueneidao‘lanluhu’le!”qinfengmuguangyining,jiangsuoyoukebenhexiticetuidaoyibian,shenxiyikouqi,zhongxinjiangzhuyilijujiaodaoneidaoxitongfabudeshuxuenantishang。
neishiyidaoyituoyuanweibeijing,jiehelehanshu、daoshu、budengshizhengmingyijicanshufanweitantaodechaojizonghedati。timutiaojianfanfu,shewencengcengdijin,jisuanlianghesiweiliangdoujiqikongbu。
ruoshisishifenzhongqian,qinfengkandaozheidaoti,kongpaliantimudoudubumingbai,gengbietijietile。
danxianzai,dangtazaicishenshizheidaotimushi,ganjuequejieranbutong。
neixiecengjingrutongluanmabandeshuxuefuhaohezhuanyeshuyu,cikezaitayanzhong,doubiandeqingximingle。tashenzhinengcongneirongzhangdetiganzhong,xunsubolichuhexindeyizhitiaojianhedaiqiuwenti。
“diyiwen,qiutuoyuancdebiaozhunfangcheng……zheigejiandan,liyonglixinlvhedianzaituoyuanshang,lianlifangchengzujike。”
qinfengdesiluyichangqingxi,naqibi,zaicaogaozhishangfeikuaidiyansuanqilai。
e=ca=22e=\frac{c}{a}=\frac{\sqrt{2}}{2}e=ac=22
x02a2+y0**2=1\frac{x_0^2}{a^2}+\frac{y_0^2}{b^2}=1a2x02+b2y02=1
a2=b2+c2a^2=b^2+c^2a2=b2+c2
jigejichugongshizaitanaohaizhongzidongfuxian,dairutimujichudejutishuzhi,yixilieyunsuanxingyunliushui。
“a²=2,b²=1。suoyituoyuancdefangchengwei:x22+y2=1\frac{x^2}{2}+y^2=12x2+y2=1。”
jinjinliangfenzhong,diyiwenbianbeitaqingsongnaxia。
“dierwen,shezhixianlyutuoyuancjiaoyua,bliangdian,ruodianp(1,1/2)manzupaxiangliang+pbxiangliang=0xiangliang,qiuzhixianldexielvk。”
“pa+pb=0,yiweizhepshiabdezhongdian。liyongdianchafahuozheweidadingli……”
qinfengdebijianzaicaogaozhishangfeiwu,gezhongjietifangfazaitanaohaizhongshanxian,bingbeixunsushaixuanchuzuiyoulujing。
shezhixianldefangchengweiy−12=k(x−1)y-\frac{1}{2}=k(x-1)y−21=k(x−1),dairutuoyuanfangcheng,xiaoquy,dedaoyigeguanyuxdeyiyuanercifangcheng。
(1+2k2)x2−(4k2−2k)x+(2k2−2k−32)=0(1+2k^2)x^2-(4k^2-2k)x+(2k^2-2k-\frac{3}{2})=0(1+2k2)x2−(4k2−2k)x+(2k2−2k−23)=0
liyongweidadinglixa+xb=4k2−2k1+2k2x_a+x_b=\frac{4k^2-2k}{1+2k^2}xa+xb=1+2k24k2−2k。
yinweipshiabzhongdian,suoyixp=xa+xb2=1x_p=\frac{x_a+x_b}{2}=1xp=2xa+xb=1。
4k2−2k2(1+2k2)=1\frac{4k^2-2k}{2(1+2k^2)}=12(1+2k2)4k2−2k=1
jiezheigeguanyukdefangcheng,dedaok=−1k=-1k=−1。
“dierwen,k=-1,yejiejuele!”qinfengdezuijiaobuzijuedigouqiyimoxiaorong。
zheizhonggongkenantide**,shitayiqiancongweitiyanguode!
zhenzhengdetiaozhan,shidisanwen。
“disanwen,zaidierwendetiaojianxia,guodianpzuozhixianmchuizhiyul,jiaotuoyuancyum,nliangdian。shiwenshifoucunzaiyigechangshuλ,shide|pm|·|pn|=λ|pa|·|pb|hengchengli?ruocunzai,qiuchuλdezhi;ruobucunzai,shuomingliyou。”
zheiyiwen,shejixianzhanggongshi、xiangliangmozhang、yijihengchengliwenti,jisuanlianghesiweinandudoudourantishenglehaojigedangci。
qinfengdemeitouweiweicuqi。
tanengganjuedao,zheiyiwendenandu,yijingchaochuletaganggangqiangxingjiyixialaideneixie“taolu”suonengzhijiejiejuedefanchou。taxuyaogengshencengcidelijiehegenglinghuodeyunyong。
“lengjing……zixifenxi……”qinfengbishangyanjing,naohaizhongganggang“tun”xiaqudewushuzhishidianrutongxingchenbanshanyao。
zhixianldexielvwei-1,zezhixianmdexielvwei1。
zhixianmdefangchengweiy−12=1(x−1)y-\frac{1}{2}=1(x-1)y−21=1(x−1),jiy=x−12y=x-\frac{1}{2}y=x−21。
jiangzhixianmdefangchengdairutuoyuanfangchengx22+y2=1\frac{x^2}{2}+y^2=12x2+y2=1,dedaoguanyuxdeyiyuanercifangcheng:
x22+(x−12)2=1\frac{x^2}{2}+(x-\frac{1}{2})^2=12x2+(x−21)2=1
x22+x2−x+14=1\frac{x^2}{2}+x^2-x+\frac{1}{4}=12x2+x2−x+41=1
32x2−x−34=0\frac{3}{2}x^2-x-\frac{3}{4}=023x2−x−43=0
6x2−4x−3=06x^2-4x-3=06x2−4x−3=0
shem(x₁,y₁),n(x₂,y₂),zex1+x2=46=23x_1+x_2=\frac{4}{6}=\frac{2}{3}x1+x2=64=32,x1x2=−36=−12x_1x_2=-\frac{3}{6}=-\frac{1}{2}x1x2=−63=−21。
∣pm∣⋅∣pn∣=(x1−xp)2+(y1−yp)2⋅(x2−xp)2+(y2−yp)2|pm|\cdot|pn|=\sqrt{(x_1-x_p)^2+(y_1-y_p)^2}\cdot\sqrt{(x_2-x_p)^2+(y_2-y_p)^2}∣pm∣⋅∣pn∣=(x1−xp)2+(y1−yp)2⋅(x2−xp)2+(y2−yp)2
youyudianm,nzaizhixiany=x−12y=x-\frac{1}{2}y=x−21shang,qiep(1,1/2)yezaizheitiaozhixianshang(yinweizhixianmguopdian),suoyipmhepndebiaodashikeyijianhua。
shijishang,pshixianmnshangdeyigedingdian。
∣pm∣⋅∣pn∣=∣(x1−xp)(x2−xp)∣⋅(1+km2)|pm|\cdot|pn|=|(x_1-x_p)(x_2-x_p)|\cdot(1+k_m^2)∣pm∣⋅∣pn∣=∣(x1−xp)(x2−xp)∣⋅(1+km2),zheilikm=1k_m=1km=1。
∣pm∣⋅∣pn∣=∣x1x2−xp(x1+x2)+xp2∣⋅(1+12)|pm|\cdot|pn|=|x_1x_2-x_p(x_1+x_2)+x_p^2|\cdot(1+1^2)∣pm∣⋅∣pn∣=∣x1x2−xp(x1+x2)+xp2∣⋅(1+12)
∣pm∣⋅∣pn∣=∣−12−1(23)+12∣⋅2=∣−12−23+1∣⋅2=∣−3+4−66∣⋅2=∣−16∣⋅2=13|pm|\cdot|pn|=|-\frac{1}{2}-1(\frac{2}{3})+1^2|\cdot2=|-\frac{1}{2}-\frac{2}{3}+1|\cdot2=|-\frac{3+4-6}{6}|\cdot2=|-\frac{1}{6}|\cdot2=\frac{1}{3}∣pm∣⋅∣pn∣=∣−21−1(32)+12∣⋅2=∣−21−32+1∣⋅2=∣−63+4−6∣⋅2=∣−61∣⋅2=31。
zheigejisuanguocheng,qinfengxiedejiweiliuchang。
jiexialaishijisuan|pa|·|pb|。
zhixianldefangchengweiy−12=−1(x−1)y-\frac{1}{2}=-1(x-1)y−21=−1(x−1),jiy=−x+32y=-x+\frac{3}{2}y=−x+23。
dairutuoyuanfangchengx22+y2=1\frac{x^2}{2}+y^2=12x2+y2=1:
x22+(−x+32)2=1\frac{x^2}{2}+(-x+\frac{3}{2})^2=12x2+(−x+23)2=1
x22+x2−3x+94=1\frac{x^2}{2}+x^2-3x+\frac{9}{4}=12x2+x2−3x+49=1
32x2−3x+54=0\frac{3}{2}x^2-3x+\frac{5}{4}=023x2−3x+45=0
6x2−12x+5=06x^2-12x+5=06x2−12x+5=0
shea(x₃,y₃),b(x₄,y₄),zex3+x4=126=2x_3+x_4=\frac{12}{6}=2x3+x4=612=2,x3x4=56x_3x_4=\frac{5}{6}x3x4=65。
tongyang,p(1,1/2)shixianabdezhongdian。
∣pa∣⋅∣pb∣=∣(x3−xp)(x4−xp)∣⋅(1+kl2)|pa|\cdot|pb|=|(x_3-x_p)(x_4-x_p)|\cdot(1+k_l^2)∣pa∣⋅∣pb∣=∣(x3−xp)(x4−xp)∣⋅(1+kl2),zheilikl=−1k_l=-1kl=−1。
youyupshiabzhongdian,suoyixp=x3+x42x_p=\frac{x_3+x_4}{2}xp=2x3+x4,zheiyiweizhex3−xp=−(x4−xp)x_3-x_p=-(x_4-x_p)x3−xp=−(x4−xp)。
yinci,∣pa∣⋅∣pb∣=∣pa∣2=(x3−xp)2(1+kl2)|pa|\cdot|pb|=|pa|^2=(x_3-x_p)^2(1+k_l^2)∣pa∣⋅∣pb∣=∣pa∣2=(x3−xp)2(1+kl2)。
x3,x4x_3,x_4x3,x4shifangcheng$6x^2-12x+5=0delianggegen。panbieshidelianggegen。panbieshidelianggegen。panbieshi\delta=(-12)^2-4\cdot6\cdot5=144-120=24>0。。。x_{3,4}=\frac{12\pm\sqrt{24}}{12}=1\pm\frac{2\sqrt{6}}{12}=1\pm\frac{\sqrt{6}}{6}。suoyi,。suoyi,。suoyi,x_3=1-\frac{\sqrt{6}}{6},,,x_4=1+\frac{\sqrt{6}}{6}(huoxiangfan,buyingxiangjieguo)。(huoxiangfan,buyingxiangjieguo)。(huoxiangfan,buyingxiangjieguo)。|x_3-x_p|=|1-\frac{\sqrt{6}}{6}-1|=\frac{\sqrt{6}}{6}。。。|pa|^2=(\frac{\sqrt{6}}{6})^2(1+(-1)^2)=\frac{6}{36}\cdot2=\frac{1}{6}\cdot2=\frac{1}{3}。suoyi,。suoyi,。suoyi,|pa|\cdot|pb|=\frac{1}{3}$。
“ng?|pm|·|pn|=1/3,|pa|·|pb|=1/3?”
qinfengkanzhecaogaozhishangdejieguo,yanzhongshanguoyisimingwu。
“ruguo|pm|·|pn|=λ|pa|·|pb|hengchengli,neimeλ=1?”
tazixijianchaleyibianzijidejisuanguocheng,meiyigebuzhoudouqingxiwuwu。
“guomubuwang”dailaidebujinjinshijiyili,haiyouyizhongduixijiedejizhidongchali,rangtahennanzaijisuanzhongchucuo。
ernei7diandezhili,suiranbugao,danzaicikeyefahuileguanjianzuoyong,rangtadeluojituilinenglishangleyigexiaotaijie。
【“guomubuwang(tiyanban)”shengyushijian:02fen15miao。】
时间所剩无几!
qinfengetouyijingbumanlehanzhu,dantayanshenqueyuelaiyueliang。
taxunsuzhenglisilu,jiangzhenggejietiguochengqingxi、wanzhengdishuxiezailingyizhangganjingdecaogaozhishang。zijisuiranyinweizhuiqiusuduerlvexianliaocao,danmeiyigebuzhoudoutiaoliqingxi,luojiyanjin。
dangtaxiexiazuihouyige“zongshangsuoshu,cunzaichangshuλ=1,shidedengshihengchengli”dejielunshi,naohaizhongdedaojishi,zhenghaotiaodaole“00fen03miao”。
“呼——”
qinfengzhangzhangdishuleyikouqi,zhenggerenrutongxutuoyiban,kaozaileyibeishang。
jihuzaitongshi,neizhongdanaorutongchaojijisuanjibangaosuyunzhuan、duiyiqiexinxiguomubuwangdeqiyiganjue,chaoshuibantuiqu。
tadedanaohuifulewangchangdezhuangtai,shenzhiyinweigangcaidechaofuheyunzhuan,haidaizheyisiqingweidepibeiheyunxuan。
dantaxinzhong,quechongmanleqiansuoweiyoudechongshiganhexiyue!
他做到了!
tajingranzhendedulijiejueleyidaoliantazijidoubuganxiangxiangdechaojinanti!
zheizhongtongguozishennuli(suiranyouxitongfuzhu)gongkenanguansuodailaidejudachengjiugan,shirenhedongxidouwufabinide!
xuexi,yuanlaiyekeyizheimeshuang!
jiuzaizheishi,binglengjixiedexitongtishiyin,ruyueerzhi:
【ding!xinshourenwu:dulizhengquejiedashuxuenanti,yiwancheng!】
【renwupingjia:youxiu(jietisiluqingxi,buzhouwanzheng,yongshi57fen57miao,fuheyuqi)。】
【zhengzaijiesuanrenwujiangli……】
qinfengdexinzangbuzhengqidijiasutiaodongqilai,yanzhongchongmanleqidai。
【gongxisuzhuhuodejiangli:10dianxueshenjifen!】
【gongxisuzhuhuodejiangli:“chujishuxuesiwei”(suipian1/3)!】
10点学神积分!
qinfengdeyanjingshunjianliangle!
zaizhiqiandexitongjieshaozhong,tayinyuejide,jifensihushixitongshangchenglideyingtonghuo,keyiyonglaiduihuangezhongshenqidedaojuhenengli!zheikeshishidashidehaodongxi!
ergengrangtajingxide,shineige“chujishuxuesiwei”suipian!
jiuzaixitongtishiyinluoxiadeshunjian,qinfengganjuedaoyiguweiruodanqueyichangxuanmiaodenuanliu,congzijimeixinchuyongrudanao。
jinjiezhe,tanaohaizhongguanyushuxuedeneixielingsande、tongguo“guomubuwang”qiangxingjiyixialaidezhishidian,fangfobeiyizhiwuxingdedashouqingqingbodongleyixia。
xuduozhiqianzhishijizhudanbingweiwanquanlijietouchedegongshidingli,cikejingranyouleyizhonghuorankailangdeganjue!
taduiganggangjiechudeneidaofuzahanshuti,yeyoulegengshenyicengdeganwu。
ruguorangtaxianzaizhongxinzuoyibian,tashenzhinengyinyueganjuedao,chulezijigangcaiyongdeneizhongjiefawai,sihuhaiyouqitagengjianjie、gengqiaomiaodesilu!
zheizhongganjuefeichangqimiao,jiuxiangshiyuanbenhundunyipiandeshuxueshijie,turanbeidianliangleyizhanxiaoxiaodemingdeng,suiranguangmangweiruo,quezuyizhaoliangyixiaopianquyu,rangtaduishuxuedeganzhihelijie,doutishengleyigeweixiaodecengci。
“zheijiushi‘chujishuxuesiwei’suipiandexiaoguoma?”qinfengxinzhongzhenhan。
jinjinshisanfenzhiyidesuipian,jiuyourucixiaoguo,neiruoshijiqilewanzhengde“chujishuxuesiwei”,shenzhishigenggaojideshuxuesiwei,neizijiqibushizhendenengchengweishuxuezhishen?
xitongdeshenqiheqiangda,zaiyicishuaxinletaderenzhi。
taditoukanlekanzijiyinweizhangshijianyongliwobieryouxiefahongdeshouzhi,youkanlekanneizhangxiemanletuiyanguochengdecaogaozhi。
suiran“guomubuwang”dexiaoguoyijingxiaoshi,dangangcaineiyigexiaoshidefengkuangxuexihejietiguocheng,queshenshendiluoyinzailetadejiyizhong。neixiebeita“tun”xiaqudezhishi,bingmeiyouwanquanxiaoshi,ershiyouyibufen,zaita7dianzhilihe“chujishuxuesiwei”suipiandeyingxiangxia,zhenzhengkaishichendianxialai,zhuanhuaweitazijidedongxi。
“xueshenheikejixitong……”qinfengdeyanzhongshanshuozheqiansuoweiyoudeguangmang。
juewangzaoyibeiyisaoerkong,querdaizhide,shixiongxiongranshaodexiwanghedouzhi!
tazhidao,congjihuozheigexitongkaishi,taderensheng,yijingchedibuyiyangle!
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ertashouzhongzhei10dianbaoguidexueshenjifen,yijineishenmide“chujishuxuesiwei”suipian,jiushitatashangzheitiaonixizhiludediyitongjin!
jiexialai,gaihaohaoyanjiuyixia,zhei10dianjifen,nengjizijidailaishenmeyangdejingxile!
qinfengdezuijiao,buyouzizhudiyangqiyimochongmanqidaidexiaorong。