2022全程班高分必刷800题答案解析新浪微博@考研数学周洋鑫12022年全程班高分必刷800题作业答案第一章函数、极限和连续【31】解析:由于0x时,1xe,10xe,则①,③正确.且0x时,10xe,1xe则②,④也正确故应选(D).【32】解析:当0x时,1xe,0x;当0x时,10xe,1x.2102100ln1limlim2lln1limn12ln1xxxxxxxexexee210lim2022xxxee.2211000ln1ln1lim2lim2limln1ln1xxxxxxxeexxee22110ln1lim20ln1xxxxxeeee2211002ln12ln1limlim21ln11ln1xxxxxxexexexex因此,原式2.【33】解析:322lim82xxaxbx2022全程班高分必刷800题答案解析新浪微博@考研数学周洋鑫2223lim8+4a0xxaxbb则32222limlim=12+4a8221xxxaxbxaxx又【34】解析:2311ln123xxxx2322220011ln123limlimxxxxxaxbxxaxbxxx232011123lim2xaxbxxx15-=0,+-2a1,22abb则1【35】解析:利用和取低阶原则tan1costanaxbxax中取,212112xxexcln+d中取cln0atan=lim2ln122xxacxc原式4ac选D【36】解析:3tantan000011tan3limlimlimlimxxxxkkkkxxxxxxxeeeexxCxxxx330113k3lim3xxcx故,【37】解析:000111+11limlimlim=11xxxxxxxeaxeaxaeaexxx洛必达12aa则-1+a1,b-4