新高考數(shù)學(xué)一輪復(fù)習(xí)第2章 第08講 函數(shù)與方程精講+精練（學(xué)生版）

第08講函數(shù)與方程(精講+精練）目錄第一部分：知識(shí)點(diǎn)精準(zhǔn)記憶第二部分：課前自我評(píng)估測試第三部分：典型例題剖析高頻考點(diǎn)一：函數(shù)零點(diǎn)所在區(qū)間的判斷高頻考點(diǎn)二：函數(shù)零點(diǎn)個(gè)數(shù)的判斷高頻考點(diǎn)三：根據(jù)零點(diǎn)個(gè)數(shù)求函數(shù)解析式中的參數(shù)高頻考點(diǎn)四：比較零點(diǎn)大小關(guān)系高頻考點(diǎn)五：求零點(diǎn)和高頻考點(diǎn)六：根據(jù)零點(diǎn)所在區(qū)間求參數(shù)高頻考點(diǎn)七：二分法求零點(diǎn)第四部分：高考真題感悟第五部分：第08講函數(shù)與方程（精練）第一部分：知識(shí)點(diǎn)精準(zhǔn)記憶第一部分：知識(shí)點(diǎn)精準(zhǔn)記憶1、函數(shù)的零點(diǎn)對(duì)于一般函數(shù)SKIPIF1<0，我們把使SKIPIF1<0成立的實(shí)數(shù)SKIPIF1<0叫做函數(shù)SKIPIF1<0的零點(diǎn)．注意函數(shù)的零點(diǎn)不是點(diǎn)，是一個(gè)數(shù).2、函數(shù)的零點(diǎn)與方程的根之間的聯(lián)系函數(shù)SKIPIF1<0的零點(diǎn)就是方程SKIPIF1<0的實(shí)數(shù)根，也就是函數(shù)SKIPIF1<0的圖象與SKIPIF1<0軸的交點(diǎn)的橫坐標(biāo)即方程SKIPIF1<0有實(shí)數(shù)根SKIPIF1<0函數(shù)SKIPIF1<0的圖象與SKIPIF1<0軸有交點(diǎn)SKIPIF1<0函數(shù)SKIPIF1<0有零點(diǎn)．3、零點(diǎn)存在性定理如果函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0上的圖象是連續(xù)不斷的一條曲線，并且有SKIPIF1<0，那么，函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0內(nèi)有零點(diǎn)，即存在SKIPIF1<0，使得SKIPIF1<0，這個(gè)SKIPIF1<0也就是方程SKIPIF1<0的根.注：上述定理只能判斷出零點(diǎn)存在，不能確定零點(diǎn)個(gè)數(shù).4、二分法對(duì)于在區(qū)間上連續(xù)不斷且SKIPIF1<0的函數(shù)SKIPIF1<0，通過不斷地把函數(shù)SKIPIF1<0的零點(diǎn)所在的區(qū)間一分為二，使區(qū)間的兩個(gè)端點(diǎn)逐步逼近零點(diǎn)，進(jìn)而得到零點(diǎn)近似值的方法叫做二分法．求方程SKIPIF1<0的近似解就是求函數(shù)SKIPIF1<0零點(diǎn)的近似值．5、高頻考點(diǎn)技巧①若連續(xù)不斷的函數(shù)是定義域上的單調(diào)函數(shù)，則至多有一個(gè)零點(diǎn)；②連續(xù)不斷的函數(shù)，其相鄰兩個(gè)零點(diǎn)之間的所有函數(shù)值保持同號(hào)；③函數(shù)SKIPIF1<0有零點(diǎn)SKIPIF1<0方程SKIPIF1<0有實(shí)數(shù)根SKIPIF1<0函數(shù)SKIPIF1<0與SKIPIF1<0的圖象有交點(diǎn)；④函數(shù)SKIPIF1<0有零點(diǎn)SKIPIF1<0方程SKIPIF1<0有實(shí)數(shù)根SKIPIF1<0函數(shù)SKIPIF1<0與SKIPIF1<0的圖象有交點(diǎn)SKIPIF1<0SKIPIF1<0，其中SKIPIF1<0為常數(shù).第二部分：課前自我評(píng)估測試第二部分：課前自我評(píng)估測試1．（2022·廣東中山·高一期末）函數(shù)SKIPIF1<0的零點(diǎn)所在的區(qū)間為（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<02．（2022·江蘇·南京市第二十九中學(xué)高一開學(xué)考試）用二分法研究函數(shù)SKIPIF1<0的零點(diǎn)時(shí)，第一次經(jīng)過計(jì)算得SKIPIF1<0，SKIPIF1<0，則其中一個(gè)零點(diǎn)所在區(qū)間和第二次應(yīng)計(jì)算的函數(shù)值分別為（

）A．SKIPIF1<0，SKIPIF1<0 B．SKIPIF1<0，SKIPIF1<0C．SKIPIF1<0，SKIPIF1<0 D．SKIPIF1<0，SKIPIF1<03．（2022·廣西玉林·高一期末）若函數(shù)SKIPIF1<0的零點(diǎn)所在的區(qū)間為SKIPIF1<0，則實(shí)數(shù)a的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<04．（2022·福建南平·高一期末）函數(shù)SKIPIF1<0的零點(diǎn)為SKIPIF1<0，SKIPIF1<0SKIPIF1<0，則SKIPIF1<0的值為（

）A．1 B．2 C．3 D．45．（2022·江蘇淮安·高一期末）已知SKIPIF1<0，SKIPIF1<0均為SKIPIF1<0上連續(xù)不斷的曲線，根據(jù)下表能判斷方程SKIPIF1<0有實(shí)數(shù)解的區(qū)間是（

）x-10123SKIPIF1<0-0.6703.0115.4325.9807.651SKIPIF1<0-0.5303.4514.8905.2416.892A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<0第三部分：典型例題剖析第三部分：典型例題剖析高頻考點(diǎn)一：函數(shù)零點(diǎn)所在區(qū)間的判斷1．（2022·江西省銅鼓中學(xué)高一開學(xué)考試）方程SKIPIF1<0的解所在的區(qū)間為（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<02．（2022·安徽·池州市第一中學(xué)高一階段練習(xí)）函數(shù)SKIPIF1<0的零點(diǎn)所在的一個(gè)區(qū)間是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<03．（2022·黑龍江·佳木斯一中高一期末）函數(shù)SKIPIF1<0的零點(diǎn)所在區(qū)間是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<04．（2022·黑龍江·雙鴨山一中高三期末（理））函數(shù)SKIPIF1<0的零點(diǎn)所在的區(qū)間為（

）SKIPIF1<0A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<0高頻考點(diǎn)二：函數(shù)零點(diǎn)個(gè)數(shù)的判斷1．（2022·安徽省蚌埠第三中學(xué)高一開學(xué)考試）已知函數(shù)SKIPIF1<0的圖像是連續(xù)不斷的，且SKIPIF1<0，SKIPIF1<0有如下的對(duì)應(yīng)值表：SKIPIF1<0123456SKIPIF1<0123.5621.45SKIPIF1<07.8211.57SKIPIF1<053.76SKIPIF1<0126.49則函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0上的零點(diǎn)有（

）A．兩個(gè) B．3個(gè) C．至多兩個(gè) D．至少三個(gè)2．（2022·山東省實(shí)驗(yàn)中學(xué)高三階段練習(xí)）已知函數(shù)SKIPIF1<0，則函數(shù)SKIPIF1<0的零點(diǎn)個(gè)數(shù)是（

）A．2 B．3 C．4 D．53．（2022·全國·模擬預(yù)測）已知函數(shù)SKIPIF1<0，則函數(shù)SKIPIF1<0的零點(diǎn)個(gè)數(shù)為（

）A．4 B．5 C．6 D．74．（2022·全國·高三專題練習(xí)）已知SKIPIF1<0，給出下列四個(gè)結(jié)論：（1）若SKIPIF1<0，則SKIPIF1<0有兩個(gè)零點(diǎn)；（2）SKIPIF1<0，使得SKIPIF1<0有一個(gè)零點(diǎn)；（3）SKIPIF1<0，使得SKIPIF1<0有三個(gè)零點(diǎn)；（4）SKIPIF1<0，使得SKIPIF1<0有三個(gè)零點(diǎn)．以上正確結(jié)論的序號(hào)是__．5．（2022·重慶九龍坡·高一期末）若函數(shù)SKIPIF1<0滿足SKIPIF1<0，且SKIPIF1<0時(shí)，SKIPIF1<0，已知函數(shù)SKIPIF1<0，則函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0內(nèi)的零點(diǎn)的個(gè)數(shù)為__________.高頻考點(diǎn)三：根據(jù)零點(diǎn)個(gè)數(shù)求函數(shù)解析式中的參數(shù)1．（2022·浙江·高三專題練習(xí)）已知函數(shù)SKIPIF1<0恰有SKIPIF1<0個(gè)零點(diǎn)，則實(shí)數(shù)SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<02．（2022·上海楊浦·高一期末）已知函數(shù)SKIPIF1<0若函數(shù)SKIPIF1<0存在零點(diǎn)，則實(shí)數(shù)a的取值范圍是（）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<03．（2022·北京大興·高一期末）若函數(shù)SKIPIF1<0恰有SKIPIF1<0個(gè)零點(diǎn)，則SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<04．（2022·福建龍巖·高一期末）若函數(shù)SKIPIF1<0在SKIPIF1<0上存在零點(diǎn)，則實(shí)數(shù)SKIPIF1<0的取值范圍是________．5．（2022·山西省長治市第二中學(xué)校高一期末）已知函數(shù)SKIPIF1<0，則使函數(shù)SKIPIF1<0有零點(diǎn)的實(shí)數(shù)SKIPIF1<0的取值范圍是____________6．（2022·全國·高三專題練習(xí)）已知函數(shù)SKIPIF1<0，SKIPIF1<0.（1）求SKIPIF1<0的解析式.（2）若方程SKIPIF1<0有實(shí)數(shù)根，求實(shí)數(shù)a的取值范圍.高頻考點(diǎn)四：比較零點(diǎn)大小關(guān)系1．（2022·浙江·於潛中學(xué)高二期中）已知函數(shù)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0的零點(diǎn)分別為a，b，c，則（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<02．（2022·河北石家莊·高三階段練習(xí)）若SKIPIF1<0，則下列不等關(guān)系一定不成立的是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<03．（2022·山東濰坊·高三期末）已知SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，則（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<04．（2022·湖北·鄂州市鄂城區(qū)教學(xué)研究室高一期末）已知方程SKIPIF1<0、SKIPIF1<0、SKIPIF1<0的根分別為a，b，c，則a，b，c的大小順序?yàn)椋?/p>

）．A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<05．（2022·江蘇蘇州·高一期末）若實(shí)數(shù)SKIPIF1<0、SKIPIF1<0滿足SKIPIF1<0，則SKIPIF1<0、SKIPIF1<0的大小關(guān)系SKIPIF1<0__SKIPIF1<0（填“SKIPIF1<0”，“SKIPIF1<0”或“SKIPIF1<0”）.6．（2022·江蘇·高一）已知函數(shù)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0的零點(diǎn)依次為SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，則SKIPIF1<0，SKIPIF1<0，SKIPIF1<0的大小關(guān)系是________．高頻考點(diǎn)五：求零點(diǎn)和1．（2022·天津市新華中學(xué)高三期末）已知函數(shù)SKIPIF1<0的定義域?yàn)镾KIPIF1<0，且SKIPIF1<0，當(dāng)SKIPIF1<0時(shí)，SKIPIF1<0若關(guān)于x的方程SKIPIF1<0在SKIPIF1<0上所有實(shí)數(shù)解的和為15，則實(shí)數(shù)k的取值范圍是(

)A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<02．（2022·安徽蚌埠·高三期末（文））已知函數(shù)SKIPIF1<0有四個(gè)不同的零點(diǎn)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，若SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，則SKIPIF1<0的值為（

）A．0 B．2 C．－1 D．－23．（2022·浙江·高三專題練習(xí)）設(shè)函數(shù)SKIPIF1<0，若互不相等的實(shí)數(shù)SKIPIF1<0、SKIPIF1<0、SKIPIF1<0滿足SKIPIF1<0，則SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<04．（2022·江蘇·高一期末）已知函數(shù)SKIPIF1<0，若存在SKIPIF1<0，使得SKIPIF1<0，則SKIPIF1<0的取值范圍是___________.5．（2022·全國·高三專題練習(xí)）已知函數(shù)SKIPIF1<0是定義在SKIPIF1<0上的奇函數(shù)，且當(dāng)SKIPIF1<0時(shí)，SKIPIF1<0，則函數(shù)SKIPIF1<0的所有零點(diǎn)的和為_________高頻考點(diǎn)六：根據(jù)零點(diǎn)所在區(qū)間求參數(shù)1．（2022·海南·高一期末）若函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0內(nèi)存在零點(diǎn)，則實(shí)數(shù)SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<02．（2022·全國·高三專題練習(xí)）函數(shù)SKIPIF1<0的一個(gè)零點(diǎn)在區(qū)間SKIPIF1<0內(nèi)，則實(shí)數(shù)SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<03．（多選）（2022·江蘇省太湖高級(jí)中學(xué)高二階段練習(xí)）函數(shù)SKIPIF1<0的一個(gè)零點(diǎn)在區(qū)間SKIPIF1<0內(nèi)，則實(shí)數(shù)a的可能取值是（

）A．0 B．1 C．2 D．34．（2022·上海市建平中學(xué)高一期末）若函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0上有零點(diǎn)，則實(shí)數(shù)SKIPIF1<0的取值范圍是________.5．（2022·湖北省廣水市實(shí)驗(yàn)高級(jí)中學(xué)高一階段練習(xí)）已知函數(shù)SKIPIF1<0，SKIPIF1<0(1)若函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0上存在零點(diǎn)，求實(shí)數(shù)a的取值范圍；高頻考點(diǎn)七：二分法求零點(diǎn)1．（2022·黑龍江·大慶中學(xué)高一期末）若函數(shù)SKIPIF1<0的一個(gè)正數(shù)零點(diǎn)附近的函數(shù)值用二分法計(jì)算，其參考數(shù)據(jù)如下：SKIPIF1<0SKIPIF1<0SKIPIF1<0SKIPIF1<0SKIPIF1<0SKIPIF1<0那么方程SKIPIF1<0的一個(gè)近似根（精確度SKIPIF1<0）可以是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<02．（多選）（2022·湖北大學(xué)附屬中學(xué)高一階段練習(xí)）某同學(xué)用二分法求函數(shù)SKIPIF1<0的零點(diǎn)時(shí)，計(jì)算出如下結(jié)果：SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，下列說法正確的有（

）A．精確到SKIPIF1<0的近似值為SKIPIF1<0 B．精確到SKIPIF1<0的近似值為SKIPIF1<0C．精確到SKIPIF1<0的近似值為SKIPIF1<0 D．精確到SKIPIF1<0的近似值為SKIPIF1<03．（多選）（2022·黑龍江·哈爾濱三中高一期末）若函數(shù)SKIPIF1<0的圖象是連續(xù)的，且函數(shù)SKIPIF1<0的唯一零點(diǎn)同在區(qū)間SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，SKIPIF1<0內(nèi)，則與SKIPIF1<0符號(hào)不同的是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<04．（多選）（2022·全國·高一）若函數(shù)SKIPIF1<0在區(qū)間SKIPIF1<0上的圖象不間斷，則下列結(jié)論中錯(cuò)誤的是（

）A．若SKIPIF1<0，則SKIPIF1<0在SKIPIF1<0上不存在零點(diǎn) B．若SKIPIF1<0，則SKIPIF1<0在SKIPIF1<0上至少有一個(gè)零點(diǎn) C．若SKIPIF1<0在SKIPIF1<0內(nèi)有且只有一個(gè)零點(diǎn)，則SKIPIF1<0 D．若SKIPIF1<0在SKIPIF1<0上存在零點(diǎn)，則可用二分法求此零點(diǎn)的近似值5．（2022·廣東汕頭·一模）為檢測出新冠肺炎的感染者，醫(yī)學(xué)上可采用“二分檢測法”、假設(shè)待檢測的總?cè)藬?shù)是SKIPIF1<0（SKIPIF1<0）將SKIPIF1<0個(gè)人的樣本混合在一起做第1輪檢測（檢測一次），如果檢測結(jié)果為陰性，可確定這批人未感染；如果檢測結(jié)果為陽性，可確定其中有感染者，則將這批人平均分為兩組，每組SKIPIF1<0人的樣本混合在一起做第2輪檢測，每組檢測1次，如此類推：每輪檢測后，排除結(jié)果為陰性的那組人，而將每輪檢測后結(jié)果為陽性的組在平均分成兩組，做下一輪檢測，直到檢測出所有感染者（感染者必須通過檢測來確定）.若待檢測的總?cè)藬?shù)為8，采用“二分檢測法”檢測，經(jīng)過4輪共7次檢測后確定了所有感染者，則感染者人數(shù)最多為______人.若待檢測的總?cè)藬?shù)為SKIPIF1<0，且假設(shè)其中有不超過2名感染者，采用“二分檢測法”所需檢測總次數(shù)記為n，則n的最大值為______.6．（2022·河南信陽·高一期末）下列函數(shù)圖象與x軸都有交點(diǎn)，其中不能用二分法求其零點(diǎn)的是___________.（寫出所有符合條件的序號(hào)）第四部分：高考真題感悟第四部分：高考真題感悟1．（2021·天津·高考真題）設(shè)SKIPIF1<0，函數(shù)SKIPIF1<0，若SKIPIF1<0在區(qū)間SKIPIF1<0內(nèi)恰有6個(gè)零點(diǎn)，則a的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<02．（2020·全國·高考真題（理））若SKIPIF1<0，則（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<03．（2020·天津·高考真題）已知函數(shù)SKIPIF1<0若函數(shù)SKIPIF1<0恰有4個(gè)零點(diǎn)，則SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<04．（2021·江蘇·高考真題）已知函數(shù)SKIPIF1<0，若其圖像上存在互異的三個(gè)點(diǎn)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，使得SKIPIF1<0，則實(shí)數(shù)SKIPIF1<0的取值范圍是__________.5．（2021·北京·高考真題）已知函數(shù)SKIPIF1<0，給出下列四個(gè)結(jié)論：①若SKIPIF1<0，SKIPIF1<0恰有2個(gè)零點(diǎn)；②存在負(fù)數(shù)SKIPIF1<0，使得SKIPIF1<0恰有個(gè)1零點(diǎn)；③存在負(fù)數(shù)SKIPIF1<0，使得SKIPIF1<0恰有個(gè)3零點(diǎn)；④存在正數(shù)SKIPIF1<0，使得SKIPIF1<0恰有個(gè)3零點(diǎn)．其中所有正確結(jié)論的序號(hào)是_______．第五部分：第08講函數(shù)與方程（精練）第五部分：第08講函數(shù)與方程（精練）一、單選題1．（2020·新疆·烏魯木齊市第三十一中學(xué)高一期末）已知函數(shù)SKIPIF1<0，則零點(diǎn)所在的區(qū)間可以為（

）A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<02．（2020·江西省興國縣第三中學(xué)高三階段練習(xí)（理））二次函數(shù)SKIPIF1<0的部分對(duì)應(yīng)值如下表：SKIPIF1<0-3-2-101234SKIPIF1<06SKIPIF1<0-4-6-6-4SKIPIF1<06可以判斷方程SKIPIF1<0的兩根所在的區(qū)間是（

）A．SKIPIF1<0和SKIPIF1<0 B．SKIPIF1<0和SKIPIF1<0C．SKIPIF1<0和SKIPIF1<0 D．SKIPIF1<0和SKIPIF1<03．（2020·全國·高一課時(shí)練習(xí)）設(shè)函數(shù)SKIPIF1<0與SKIPIF1<0的圖象交點(diǎn)為SKIPIF1<0，則SKIPIF1<0所在區(qū)間是（

）A．(0，1) B．(1，2) C．(2，3) D．(3，4)4．（2020·四川·廣安二中高一期中）函數(shù)SKIPIF1<0的一個(gè)正數(shù)零點(diǎn)附近的函數(shù)值用二分法逐次計(jì)算，參考數(shù)據(jù)如下：SKIPIF1<0

SKIPIF1<0

SKIPIF1<0SKIPIF1<0

SKIPIF1<0

SKIPIF1<0那么方程的一個(gè)近似解（精確度為0.1）為（

）A．1.5 B．1.25 C．1.41 D．1.445．（2020·全國·高三專題練習(xí)）已知函數(shù)SKIPIF1<0，若方程SKIPIF1<0有四個(gè)不同的解SKIPIF1<0且SKIPIF1<0，則SKIPIF1<0的取值范圍是（

）A．SKIPIF1<0 B．SKIPIF1<0 C．SKIPIF1<0 D．SKIPIF1<06．（2020·全國·高三專題練習(xí)）已知函數(shù)SKIPIF1<0，SKIPIF1<0，SKIPIF1<0的零點(diǎn)分別為SKIPIF1<0，SKIPIF1<0，SKIPIF1<0，則（

）．A．SKIPIF1<0 B．SKIPIF1<0C．SKIPIF1<0 D．SKIPIF1<07．（2020·四川·廣安二中高一期中）已知函數(shù)SKIPIF1<0，其中SKIPIF1<0，若存在實(shí)數(shù)SKIPIF1<0，使得關(guān)于SKIPIF1<0