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1、指数函数知识点总结(一)指数与指数幂的运算1根式的概念:一般地,如果,那么叫做的次方根,其中1,且*负数没有偶次方根;0 的任何次方根都是0,记作。当是奇数时,当是偶数时,2分数指数幂正数的分数指数幂的意义,规定:,0 的正分数指数幂等于0,0 的负分数指数幂没有意义3实数指数幂的运算性质(1);(2);(3)(二)指数函数及其性质1、指数函数的概念:一般地,函数叫做指数函数,其中x 是自变量,函数的定义域为R注意:指数函数的底数的取值范围,底数不能是负数、零和12、指数函数的图象和性质a1 0a1(0a0(x0)个单位,则得到函数y ax+b的图像;把函数 yax文档编码:CY4J6I9W2
2、R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9
3、L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2
4、R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9
5、L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2
6、R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9
7、L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2
8、R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3的图像向右平移b(b0)个单位,则得到函数yax-b的图像;把函数yax的图像向上平移b(b0)个单位,则得到函数yax+b 的图像;把函数 yax的图像向下平移b(b0)个单位,则得到函数yaxb 的图像(左加右减,上加下减)(2)对称变换:函数yax的图像与函数ya-x的图像关于y 轴对称;函数y-ax的图像与函数yax的图像关于x 轴对称;函数y-a-x的图像与函数yax的图像关
9、于原点对称;函数ya|x|的图像关于y轴对称.例:为了得到函数935xy的图象,可以把函数3xy的图象()A 向左平移9 个单位长度,再向上平移5 个单位长度B 向右平移9 个单位长度,再向下平移5 个单位长度C 向左平移2 个单位长度,再向上平移5 个单位长度D 向右平移2 个单位长度,再向下平移5 个单位长度分析:注意先将函数935xy转化为235xt,再利用图象的平移规律进行判断解:293535xxy,把函数3xy的图象向左平移2 个单位长度,再向上平移5 个单位长度,可得到函数935xy的图象,故选(C)评注:用函数图象解决问题是中学数学的重要方法,利用其直观性实现数形结合解题,所以要
10、熟悉基本函数的图象,并掌握图象的变化规律,比如:平移、伸缩、对称等比较两个有理数指数幂的大小:(1)比较幂的大小常用方法:比差(商)法;函数单调性法;中间值法:要比较A与 B 的大小,先找一个中间值C,在比较A与 C,B与 C的大小,由不等式的传递性得到A与 B的大小;(2)用指数函数单调性比较大小,基本步骤:确定所要考察的指数函数;根据底数情况指出已确定的指数函数的单调性;比较指数的大小,利用指数函数单调性得出同底数幂的大小关系.(3)常用技巧:对于底数相同、指数不同的两个幂的大小比较,可利用指数函数单调性判断;对于底数不同,指数相同的两个幂的大小比较,可利用指数函数图像变化规律来判断;对于
11、底数不同指数也不同的两个幂的大小比较,则应通过中间量来比较;对于3 个或以上的数的大小比较,则应先根据值的大小(特别是与0、1 的大小)进行分组,在比较各组数的大小即可.(4)异底指数比较大小的五种技巧:化同底:因为化为同底后即可应用指数函数单调性解决,所以能化同底的尽可能化;商比法:不同底但可以化为同指数的两数比较大小,用商比法即可,这时要注意分母的正负;例:比较下列两数大小:1.1-0.2和 1.3-0.1。文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9
12、W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7
13、J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9
14、W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7
15、J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9
16、W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7
17、J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9
18、W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3取中间值:不同底也不同指数宜先与中间值0、1 比较大小,在间接得解;估算法:大致估算数值;图解法:借助图像例:比较下列各组数的大小:(1)若,比较与;(2)若,比较与;(3)若,且,比较a与b;(4)若,且,比较a与b解:(1)由,故又,故从而(2)由,因,故又,故从而(3)应有因若,则又,故,这样又因,故从而,这与已知矛盾(4)应有 因若,则 又,故,这样有 又因,且,故从而,这与已知矛盾小结:比较通常借助相应函数的单调性、奇偶性、图象来求解例:曲线分别是指数函数,和的图象,则与 1 的大小关系是().(分 析:首先可以根据指数函数单调
19、性,确定,在轴右侧令文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6
20、I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 Z
21、H7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6
22、I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 Z
23、H7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6
24、I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 Z
25、H7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3,对应的函数值由小到大依次为,故应选.小结:这种类型题目是比较典型的数形结合的题目,第(1)题是由数到形的转化,第(2)题则是由图到数的翻译,它的主要目的是提高学生识图,用图的意识.例:将下列各数从小到大排列起来.35322-6523523,533231-31-303221212131-),(),(),(),(),(),(),()(与指数
26、函数相关的定义域值域问题:(1)求由指数函数构成的复合函数的定义域时,可能涉及解指数不等式(即未知数在指数上的不等式)解指数不等式的基本方法是把不等式两边化为同底数幂的形式,利用函数单调性去幂的形式;(2)求定义域方法:yaf(x)的定义域与函数y=f(x)的定义域相同;y=f(ax)的定义域与函数y=f(x)的定义域不一定相同,求其定定义域时,应通过复合函数定义由f(x)的定义域与g(x)=ax的值域的等价性,建立关于x 的不等式,利用指数函数相关性质求解.(3)求值域方法:求 yaf(x)的值域时,先求函数y=f(x)的值域,再根据指数函数单调性确定函数yaf(x)的值域;求 y=f(ax
27、)的值域时,可用换元法求解,但换元后应注意引入新变量的取值范围;(4)几种基本形式的的定义域与值域问题:形如 y af(x)的函数的定义域就是y=f(x)的定义域;形如 yaf(x)的函数的值域,应该先求出f(x)的值域,再由单调性求出值域,若a 范围不确定,则需对a论进行讨论;形如求 y=f(ax)的值域,要先求出u=ax的值域,再结合y=f(u)确定出值域.例求函数216xy的定义域和值域文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6
28、P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档
29、编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6
30、P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档
31、编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6
32、P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档
33、编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6
34、P1M9M7 ZH7J9L7J7F3解:由题意可得2160 x,即261x,20 x,故2x,函数()f x 的定义域是2,令26xt,则1yt,又2x,20 x 2061x,即 01t 011t,即01y,函数的值域是01,评注:利用指数函数的单调性求值域时,要注意定义域对它的影响练习 1:已知-1x2,求函数 f(x)=3+2 3x+1-9x的最大值和最小值解:设 t=3x,因为-1 x2,所以931t,且 f(x)=g(t)=-(t-3)2+12,故当 t=3 即 x=1 时,f(x)取最大值12;当 t=9 即 x=2 时 f(x)取最小值-24。练习 2:已知函数(且)(1)求的最小
35、值;(2)若,求的取值范围解:(1),当即时,有最小值为(2),解得当时,;当时,例:已知,求函数的值域解:由得,即,解 之 得,于 是,即,故所求函数的值域为指数型复合函数单调性:判断形如y=af(x)(a0 且 a 不等于 1)的函数单调性方法:1、利用单调性定义,取值-作差-变形-定号.2、利用复合函数单调性:令 u=f(x),xnm,复合的两个函数y=au与 u=f(x)的单调性如果相同,则复合后的函数y=af(x)在上是增函数;若两者单调性相反,则其在定义域上是减函数.例:讨论函数xxxf22)51()(的单调性,并求其值域.nm,文档编码:CY4J6I9W2R9 HU1Y6P1M9
36、M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:C
37、Y4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9
38、M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:C
39、Y4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9
40、M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:C
41、Y4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9
42、M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3例:求函数 y23231xx的单调区间.分析这是复合函数求单调区间的问题可设 yu31,u x2-3x+2,其中 yu31为减函数u x2-3x+2 的减区间就是原函数的增区间(即减减增)ux2-3x+2 的增区间就是原函数的减区间(即减、增减)解:设 yu31,u x2-3x+2,y关于 u 递减,当 x(-,23)时,u 为减函数,y 关于 x 为增函数;当 x23,+)时,u 为增函数,y 关于 x 为
43、减函数.例:求函数xxy4212的单调区间.文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7
44、F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 H
45、U1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7
46、F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 H
47、U1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7
48、F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 H
49、U1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3指数函数综合应用:与奇偶性结合例:设 a0,f(x)=xxeaae是定义在R上的偶函数.(1)求 a 的值.(2)证明 f(x)在(0,)上是增函数.练习:若函数1212)(xxaaxf为奇函数.(1)确定 a 的值;(2)求函数f(x)的定义域;(3)求函数f(x)的值域;(4)讨论 f(x)单调性.练习:已知函
50、数2()()21xf xaaR,(1)求证:对任何,()aR f x为增函数;(2)若()f x为奇函数时,求a 的值。文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3文档编码:CY4J6I9W2R9 HU1Y6P1M9M7 ZH7J9L7J7F3