河北省献县2023-2024学年八年级第一次学情评估数学.试卷答案,我们目前收集并整理关于河北省献县2023-2024学年八年级第一次学情评估数学.得系列试题及其答案，更多试题答案请关注微信公众号：趣找答案/直接访问www.qzda.com(趣找答案)

河北省献县2023-2024学年八年级第一次学情评估数学.试卷答案

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firetomeloffthefat."Therealevidenthatwehavehastodowiththebreakagepatterns,andhowthrougtheyTheymusthaveusedrocksohamerbutheskeapaThesepeopeouhtevertheyo"RowetodUSAT32.WhatcanbelearntabouttheearliesthumansinNorthAmerica?A.Theyarrivedthere16,000yearsago.B.Theycausedmammothtodisappear.C.TheybelongedtotheClovisculture.D.Theycouldmaketoolswithbones.33.Whyarethefindingssimilartothenewoneignored?A.Theylackagoodchance.B.Theyfailtodrawattention.C.Theydisagreewithearlierresearch.D.Theyaren'tstudiedscientifically.34.HowdoesRowefindthenewdiscovery?A.Annoying.B.Inspiring.C.Puzzling.D.Embarrassing.35.Whatcanbeasuitabletitleforthetext?A.EvidenceofEarlierHumans'ArrivalinNorthAmericaB.TheEarliestHumans'SettlinginNorthAmericaC.TheEarliestToolMakersinNorthAmericaD.ResearchonMammothsinNorthAmerica第二节（共5小题；每小题2.5分，满分12.5分）阅读下面短文，从短文后的选项中选出可以填人空白处的最佳选项

选项中有两项为多余选项

Travelinginthesamecarwithseveralpeopleisanexcellentidea,whichallowsonetosaveonfuel.Inthepast,fewofuswouldgotothecompanyorworkplacetogether.36Weshareacareverydaywithpeoplewhomwedonotknowanythingabout.WejustneedtoconnecttotheInternetoruseamobileapptofindtheperfecttransportforus.37Itmakespracticalsensetousetoolsatourhandstoconnectwithpeoplewhowouldliketosharecarstogether.Toolslikemobileappshelpcontributetosharingoptions.Undoubtedly,carpooling(isanexcellentoptiontosavesomemoney.Italsoad-justsourmonthlybudgetforotheractivities,butthetruthisthatthistypeoftransportisalsomuchbettersuitedtoimprovethetrafficconditionsofcities.38Practicallyspeakingmanytimes,weseeheavytrafficbutuponfurtherfindingwewouldseemanycarswithonlyonepassengerinit.Ratherthanbeingaloneinaheavytrafficsituation.whynothavepassengers?39Atthesametime,youcanalsohaveamazingconversations.Spendingontransportationispartofwhatweconsidertobefixedexpensesinafamily,whethertomovetowork,tostudyorsimplybecauseweliveinareasfarawayfromthelargeurbancenters.40It'sspeciallyfitforthosewhowanttospendlessonfuelorwouldlovetohaveaneco-friendlyapproachfortheenvironment.A.Carpoolingisalsofitforlongroutes.【高三英语第7页（共10页）】·23-144C·

分析（1）由已知条件分别求出投篮命中率、投篮不被拦截率及该运动员的进攻率，由此能求出在三分线（约距球篮6.72米）处的进攻成功率．
（2）由已知条件利用均值定理能求出在距球篮几米处的进攻成功率最大，并能求出最大进攻成功率．

解答解：（1）依题意，投篮命中率为100%-10%[x]，投篮不被拦截率为$1-\frac{90%}{[x]+1}$；
故该运动员的进攻率（设为y）为y=（1-$\frac{90%}{[x]+1}$）（100%-10%[x]）=$（1-\frac{90%}{[x]+1}）（1-0.1[x]）$
设[x]+1=t，则[x]=t-1，y=（1-$\frac{0.9}{t}$）（1.1-0.1t）=1.19-（0.1t+$\frac{0.99}{t}$），
当x=6.72时，t=[6.72]+1=7，y≈0.35=35%．
（2）∵$0.1t+\frac{0.99}{t}≥2\sqrt{0.1t•\frac{0.99}{t}}$，
当且仅当$0.1t=\frac{0.99}{t}$，即t≈3.15取等号．
但t∈N^*，∴t=3或4时，y可能有最大值，当t=3时，y=0.56，当t=4时，y=0.54，
∴当t=3时，y有最大值0.56，这时[x]=2，即2≤x＜3．
答：在三分线处进攻率为35%，在距离球篮2至3米的进攻成功率最大，最大成功率为56%．

点评本题考查概率在生产生活中的实际运用，是中档题，解题时要认真审题，注意均值定理的合理运用．

河北省献县2023-2024学年八年级第一次学情评估数学.