2022考研数学满分过关1501第三章一元函数积分学重点题型一不定积分的计算【例3.1】设21()1cosfxx=+,则()fx在[]0,π上的所有原函数是__________.【详解】2222sectan1tanarctan1cossec12tan22dxxdxxdxCxxx===++++∫∫∫令1tanarctan,02222()0,21tanarctan,2222xxFxxxxππππππ−≤<==+<≤则()fx在[]0,π上的所有原函数是()FxC+,其中C为任意常数.【例3.2】计算下列积分:(1)(江苏省2004年竞赛题)2(1)()xxexdxxe−−∫;(2)21ln(ln)xdxxx−−∫;(3)(南京大学1995)1(1)xxdxxxe++∫;(4)sincos1(1)xxxdxxxe++∫;(5)254cos(2cos)sinxdxxx++∫;(6)22sin2(cossin)xxdxxxx+−∫;(7)33sinsincosxdxxx+∫.V研客2022考研数学满分过关1502【详解】(1)2222(1)(1)11()11xxxxxxxexexexxdxdxdCxexxeeexx−−==−−=+−−−−∫∫∫(2)22221ln1ln1ln1(ln)lnlnln11xxxxxdxdxdCxxxxxxxxx−−==−−=+−−−−∫∫∫(3)1(1)()11()ln(1)(1)(1)11xxxxxxxxxxxxxxedxexedxdxdxeCxxexexexexexexexe++===−=++++++∫∫∫∫(4)sinsinsinsinsinsinsinsinsinsinsinsincos1(cos1)()(1)(1)(1)11()ln11xxxxxxxxxxxxxxxxedxedxdxxxexexexexexedxeCxexexe++==+++=−=+++∫∫∫∫(5)222222254cos(54cos)sin54coscos(2cos)sin(2cos)sin(2cos)(1cos)11111coscosln(2cos)1cos2cos21cosxxxxdxdxdxxxxxxxxdxCxxxx+++==−+++−+=−+=−++−+−∫∫∫∫(6)22222sin2sectan(1tan)222(cossin)(1tan)(1tan)1tanxxxxxdxxdxdxCxxxxxxxxx++−==−=+−−−−∫∫∫V研客2022考研数学满分过关1503(7)233333222222tansintansectantansincostan1tan111(1)(1)1113(1)(1)31311(1)6xuxxxxudxdxdxduxxxxuuuuudududuuuuuuuduuuu===+++++−−++==−+−+−++−+=−∫∫∫∫∫∫∫22221111ln11223314211211ln(1)arctanln163331tantan112tan1lnarctan6(tan1)33duuuuuuuCxxxCx+−−+++−−=−++−++−+−=+++∫∫【例3.3】计算下列积分:(1)3(1)(2)dxxx−−∫;(2)243(1)(1)dxxx+−∫;(3)111xdxxx−+∫;(4)11xxedxe−+∫.【详解】(1)【方法一】2311112122(1)111(1)(2)11dxxxdxdCxxxxxxx−−==−=+−−−−−−−−∫∫∫【方法二】332223211121121(2)221(1)(2...