复合函数的单调性典型习题

复合函数的单调性练习题山东王宪华._____________,)21(.1322减区间为的增区间为xxy._____________,2.2822减区间为的增区间为xxy._______________,)32(log.322减区间为的增区间为xxy.______________,)82-(log4.22减区间为的增区间为xxy的取值范围上是减函数，求在且aaaaxya]1,0[)1,0)(2(log5..3-13-)(,)(log)(6.25.0的取值范围求）上是增函数，，在（且的值域为axfRaaxxxf参考答案]1,(:),,1[:.1减区间为增区间为]4,1[:]1,2[.2，减区间为增区间为：)1,(:),,3(:.3减区间为增区间为)4,1[:],1,2(:.4减区间为增区间为21:)2)(1()2......(..................................................1),0(log.]2,0[)2(log,0,]2,0[2]2,0[,2slog]1,0[),1(log)1........(..........2021,]1,0[2,0.]1,0[)2(log,02],1,0[]1,0[)1,0)(2(log5minaaatyaxysaxsxaxsyxaxyaasaxsaaxyaxsxaaaxyaaaaaa的取值范围为式可知由上是增函数在知由复合函数的单调性可上是减函数在且上是减函数在而的复合函数，与是上是减函数在上且递减在且上是减函数在且解)1...(..................................................04,)(log)(6.2225.0aaaaxxsRaaxxxf可以取到所有正实数的值域为解上是增函数在且上是增函数，，在)31,3()(log)()2.(....................0),31,3()3-13-()(log)(25.0225.0aaxxxfaaxxsxaaxxxf0)31()31()2()3........(..........312:)31,3(:)31,3()(log),0(log)31,3(,log)31,3(),(log)(2225.05.025.02aaaaaxxsaaxxysyxaaxxssyxaaxxxfa且由二次函数的图象可知上是减函数在知由复合函数的单调性可上是增函数在是减函数，在而的复合函数与是200)31()31(31204)3)(2)(1(22aaaaaaa解得：同时满足综上可知