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1、学习好资料欢迎下载第一讲函数的解析式的求法求函数的解析式是函数的常见问题,也是高考的常规题型之一,方法众多,下面对一些常用的方法一一辨析.一换元法题 1已知 f(3x+1)=4x+3,求 f(x)的解析式.练习 1若xxxf1)1(,求)(xf.二配变量法题 2已知221)1(xxxxf,求)(xf的解析式.练习 2若xxxf2)1(,求)(xf.三待定系数法题 3设)(xf是一元二次函数,)(2)(xfxgx,且212)()1(xxgxgx,求)(xf与)(xg.练习 3设二次函数)(xf满足)2()2(xfxf,且图象在 y 轴上截距为 1,在x 轴上截得的线段长为22,求)(xf的表达式
2、.学习好资料欢迎下载四解方程组法题 4设函数)(xf是定义(,0)(0,+)在上的函数,且满足关系式xxfxf4)1(2)(3,求)(xf的解析式.练习 4若xxxfxf1)1()(,求)(xf.五特殊值代入法题 5若)()()(yfxfyxf,且2)1(f，求值)2004()2005()3()4()2()3()1()2(ffffffff.练习 5 设)(xf是定义在N上的函数,且2)1(f,21)()1(xfxf，求)(xf的解析式.六利用给定的特性求解析式.题 6设)(xf是偶函数,当 x0 时,xexexf2)(,求当 x0 时，)(xf的表达式.练 习6 对x R,)(xf满 足)1(
3、)(xfxf,且 当x 1,0 时,文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档
4、编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1
5、U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档
6、编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1
7、U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档
8、编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1
9、U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5学习好资料欢迎下载xxxf2)(2求当 x9,10 时)(xf的表达式.七归纳递推法题 7设11)(xxxf,记)()(xfffxfn,求)(2004xf.八相关点法题 8 已知函数12)(xxf,当点 P(x,y)在 y=)(xf的图象上运动时,点 Q(3,2xy)在 y=g(x)的图象上,求函数 g(x).九构造函数法
10、题 9 若)(xf表示 x 的 n 次多项式,且当 k=0,1,2,n 时,1)(kkkf，求)(xf.课堂小结：求函数的解析式的方法较多，应根椐题意灵活选择，但不论是哪种方法都应注意自变量的取值范围，对于实际问题材，同样需注意这一点，应保证各种有关量均有意义。练习：1向高为 H的水瓶中注水,注满为止,如果注水量 V与水深 h 的函数关系如图所Y X 文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编
11、码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U
12、2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编
13、码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U
14、2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编
15、码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U
16、2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5学习好
17、资料欢迎下载示,那么水瓶的形状是2从盛满 20 升纯洒精的容器中倒出1 升,然后用水填满,再倒出 1 升混合溶液后又用水填满,这样继续下去,如果第 k 次倒后共倒出纯洒精x 升,第 k+1次倒后共倒出纯洒精 f(x)升,求 f(x)的表达式.(f(x)=12019x)3设二次函数)(xf满足)2()2(xfxf,且它的图象与 y 轴交于点(0,1),在x 轴上截得的线段长为22,求)(xf的表达式.(1)2(21)(2xxf)4 对满足1x的所有实数 x,函数)(xf满足xxxfxxf)13()13(,求所有可能的)(xf.(23227)(xxxxf,(1x)5设)(xf是定义在N上的函数,若
18、1)1(f,且对任意的 x,y 都有：xyyxfyfxf)()()(,求)(xf.()1(21)(2xxf)求 函 数 解 析 式文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L
19、4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V
20、8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L
21、4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V
22、8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L
23、4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V
24、8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5学习好资料欢迎下载教学目标：使学生明确待定系数法、换元法、配凑法是求函数解析式常用的方法，并会用这些方法求函数解析式重点、难点：重点：待定系数法求函数解析式。难点：换元法与配凑法求函数解析式教学方法：讲练结合法学生已熟悉用待定系数
25、法求一次、二次函数解析式，但用换元法和配凑法求函数解析式并不熟悉，特别是求出函数解析式后要注明函数定义域易被学生忽视，所以通过讲、练要解决好这些问题，特别要使学生明确函数定义域是函数概念中重要组成部分。教学设计：新课引入用待定系数法求函数解析式用换元法与配凑法求函数解析式 课时小结 随堂练习教学过程：1、新课引入：复习提问：求函数定义域的关键是什么？函数三要素是什么？（求函数定义域的关键是确定使函数有意义的条件。函数三要素是对应法则、定义域与值域）导入新课：如何根据条件，求出函数对应法则即函数解析式是函数又一重要问题。板书课题：求函数解析式2、用待定系数法求函数解析式例 1：已知函数f(x)是
26、一次函数，且满足关系式3f(x+1)-2f(x-1)=2x+17,求 f(x)的解析式。例 2：求一个一次函数f(x)，使得 fff(x)=8x+7 分析：这两个例题的共同点，所求的函数类型已定，都是一次函数。这种函数解析式用什么方法来求？（待学生回答后，老师继续讲）如何剥掉抽象的对应法则符号成了解答这两题的关键，如例1：若设 f(x)=ax+b(a 0)则 f(x+1)=?f(x-1)=?如例 2：设 f(x)=ax+b(a 0)则 fff(x)=ffax+b=fa(ax+b)+b=?解答由学生作出解答）例 1.解：设 f(x)=ax+b(a 0)由条件得：3a(x+1)+b-2a(x-1)
27、+b=ax+5a+b=2x+17 f(x)=2x+7 例 2.解：设 f(x)=ax+b（a0)依题意有 aa(ax+b)+b+b=8x+7 xa3+b(2a+a+1)=8x+7 f(x)=2x+1 文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5
28、文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2
29、I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5
30、文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2
31、I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5
32、文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2
33、I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5学习好资料欢迎下载评注：待定系数法是一种重要的数学方法，它适用于已知所求函数的类型，求此函数。3、用换元法与配凑法求函数解析式例 3：已知 f(x+1)=x+2
34、x，求 f(x)的解析式分析：是否知道所求函数f(x)的类型？（待学生回答后，老师继续讲）若把x+1 看作一个整体，该用什么方法作？（待学生回答，让学生作出解答）解 1：令 t=x+11 则 x=2)1(t f(t)=2)1(t+2(t-1)=2t-1 f(x)=2x-1(x1)解 2：由 f(x+1)=x+2x=2)1(x-1 f(x)=2x-1(x1)学生容易忽视函数的定义域，就此例题向学生发问：师问：f(x)=2x-1 与 f(x)=2x-1(x1)是否是同一函数？那么求函数解析式后是否要注明函数定义域评注：(1)f(t)与 f(x)只是自变量所用字母不同，本质是一样的。(2)求出函数解
35、析式时，一定要注明定义域，函数定义中包括定义域这一要素。例 4：已知 f(x-1)=2x-4x，解方程f(x+1)=0 分析：如何由f(x-1)，求出 f(x+1)是解答此题的关键（由老师讲解）解 1：f(x-1)=2)1(x-2(x-1)-3 f(x)=2x-2x-3 f(x+1)=2)1(x-2(x+1)-3=2x-4 2x-4=0 x=2 解 2：f(x-1)=2x-4x f(x+1)=f（x+2)-1=2)2(x-4(x+2)=2x-4 2x-4=0，x=2 解 3：令 x-1=t+1 则 x=t+2 f(t+1)=2)2(t-4(t+2)=2t-4 f(x+1)=2x-4 2x-4=
36、0 x=2 评注：只要抓住关键，采用不同方法都可以达到目的。解法1，采用配凑法；解法2，根据对应法则采用整体思想实现目的；解法3，采用换元法，这些不同的解法共同目的是将 f(x-1)的表达式转化为f(x+1)的表达式。4、课时小结：待定系数法、换元法、配凑法是求函数解析式常用的方法，其中，待定系数法只适用于已知所求函数类型求其解析式，而换元法与配凑法所依据的数字思想完全相同-整体思想。文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1
37、O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:C
38、A2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1
39、O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:C
40、A2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1
41、O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:C
42、A2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1
43、O9 ZK3W4L4B9H5学习好资料欢迎下载随堂练习：1、已知 f(x+1)=2x+1，求 f(x)解析式。2、设函数F(x)=f(x)+g(x)其中f(x)是 x 的正比例函数，g(x)是2x的反比例函数，又F(2)=F(3)=19,求 F（x)的解析式。课外作业：1、已知 f(x)是一次函数，且ff(x)=4x-1,求 f(x)的解析式。2、设 f(x)=22x-3x+1,g(x-1)=f(x),求 g(x)及 f g(2).文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档
44、编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1
45、U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档
46、编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1
47、U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档
48、编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1
49、U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5文档编码:CA2R9F2M4V8 HV2I1U2P1O9 ZK3W4L4B9H5