《函数》练习(一)222121)4(,1)(.1DCBAxxfxxxf的根是则方程若2224144414441021021012xfxxxxxxxxxxxA,3,11,1,13,0,2log)(.231DCBAxxxf的值域是函数13min()log20,3,3,()(3)1()1fxxxfxffx在上是减函数时C)41()4()31()3()21()2()1(,1)(.322fffffffxxxf则已知函数22222111(),()1111xxfxfxxxx11()()1,(1)217322fxffx又原式27的定义域为函数2231.4xxy22320,23013031xxxxxxx得31xx的表达式为则函数的图象经过点又其反函数的图象经过点若函数)(0471)(.51xf,,xf,,kaxfx10,()(1,7)(0,4)47()4334xfxaakfxkak解析,由题意知过点和()43xfx251,31,1)(.6ffxxxxxf则已知551()3222f1131222f原式32的定义域是则函数的定义域为已知函数)1()1(21)(.72xfxf,,xf211231112xxx由得[3,1].,,,,13:,,,374,321.823的值求实数映射且已知集合kaByAxxyxfZkZaaa,a,,Bk,,,A(1)4,(2)7,(3)1010fffB解3210(),31025aaZaaa若则无解故或3372,()231835,()53112542afkkkkZafkkk当时即与矛盾当时即答:实数a的值为-5,实数k的值为-42.).(,12)()(3);(,34)(2),()(,52)1(1.92xfxxfxfxfxfxxff,xfxfxfxxf求满足若求且是一次函数若与求若22(1)1,1()2(1)527()27()27txxtftttfxxfxx设则2()(0)()()()()fxkxbkffxkfxbkkxbkxkxb(2)设则2()43224133()21()23ffxxkkkbbkbbfxxfxx又或或21(3)()2()11()2()2()(0)3fxfxxffxxxxfxxx由得易求得).(,12)()(3);(,34)(2),()(,52)1(1.92xfxxfxfxfxfxxff,xfxfxfxxf求满足若求且是一次函数若与求若。babbaxxf的值求和值域都是的定义域若函数,),1(,1)1(21)(.1022minmax2()11,(1)2111(113(1)2fxyaybaaaabbbab解:函数在,b上单调递增,依题意知舍去)或1,3.ab所求的值为的值为