（江苏专用）高考数学一轮复习 第二章 函数概念与基本初等函数I 2.8 函数与方程 理-人教版高三全册数学试题VIP专享VIP免费

【步步高】（江苏专用）2017版高考数学一轮复习第二章函数概念与基本初等函数I2.8函数与方程理INCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\基础知识自主学习.tif"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\基础知识自主学习.tif"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\基础知识自主学习.tif"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\基础知识自主学习.tif"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\基础知识自主学习.tif"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\知识梳理.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\知识梳理.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\知识梳理.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\知识梳理.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\知识梳理.TIF"\*MERGEFORMATINET1．函数的零点(1)函数零点的定义对于函数y＝f(x)(x∈D)，把使函数y＝f(x)的值为0的实数x叫做函数y＝f(x)(x∈D)的零点．(2)几个等价关系方程f(x)＝0有实数根⇔函数y＝f(x)的图象与x轴有交点⇔函数y＝f(x)有零点．(3)函数零点的判定(零点存在性定理)如果函数y＝f(x)在区间[a，b]上的图象是一条不间断的曲线，且f(a)·f(b)<0，那么，函数y＝f(x)在区间(a，b)上有零点，即存在c∈(a，b)，使得f(c)＝0，这个__c__也就是方程f(x)＝0的根．2．二分法对于在区间[a，b]上连续不断且f(a)·f(b)<0的函数y＝f(x)，通过不断地把函数f(x)的零1点所在的区间一分为二，使区间的两个端点逐步逼近零点，进而得到零点近似值的方法叫做二分法．3．二次函数y＝ax2＋bx＋c(a>0)的图象与零点的关系Δ>0Δ＝0Δ<0二次函数y＝ax2＋bx＋c(a>0)的图象INCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-70.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-70.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-70.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-70.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-70.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-71.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-71.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-71.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-71.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-71.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-72.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-72.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-72.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-72.TIF"\*MERGEFORMATINETINCLUDEPICTURE"E:\\赵丽君2016\\一轮2016\\数学\\苏教（理）\\word\\2-72.TIF"\*MERGEFORMATINET2与x轴的交点(x1,0)，(x2,0)(x1,0)无交点零点个数210【思考辨析】判断下面结论是否正确(请在括号中打“√”或“×”)(1)函数的零点就是函数的图象与x轴的交点．(×)(2)函数y＝f(x)在区间(a，b)内有零点(函数图象连续不断)，则f(a)·f(...