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專題07函數(shù)的奇偶性專項突破一奇偶性的判斷或證明1.下列函數(shù)中是奇函數(shù)的是(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【解析】對于A,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,故SKIPIF1<0為非奇非偶函數(shù),對于B,SKIPIF1<0,定義域為SKIPIF1<0,SKIPIF1<0,SKIPIF1<0為偶函數(shù),對于C,SKIPIF1<0,SKIPIF1<0為偶函數(shù),對于D,易知定義域為R,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0為奇函數(shù).故選:D2.已知函數(shù)SKIPIF1<0,則(
)A.SKIPIF1<0是奇函數(shù) B.SKIPIF1<0是奇函數(shù) C.SKIPIF1<0是偶函數(shù) D.SKIPIF1<0是偶函數(shù)【解析】對于A,SKIPIF1<0SKIPIF1<0,SKIPIF1<0SKIPIF1<0SKIPIF1<0且SKIPIF1<0,SKIPIF1<0的定義域不關(guān)于原點對稱,函數(shù)不具有奇偶性,故A錯誤,對于B,SKIPIF1<0SKIPIF1<0,SKIPIF1<0SKIPIF1<0SKIPIF1<0且SKIPIF1<0,所以SKIPIF1<0的定義域關(guān)于原點對稱,又SKIPIF1<0,所以SKIPIF1<0為奇函數(shù),故B正確,對于C,SKIPIF1<0SKIPIF1<0,SKIPIF1<0SKIPIF1<0SKIPIF1<0且SKIPIF1<0,SKIPIF1<0的定義域不關(guān)于原點對稱,函數(shù)不具有奇偶性,故C錯誤,對于D,SKIPIF1<0SKIPIF1<0,SKIPIF1<0SKIPIF1<0SKIPIF1<0且SKIPIF1<0,所以SKIPIF1<0的定義域關(guān)于原點對稱,又SKIPIF1<0,所以函數(shù)SKIPIF1<0是奇函數(shù),故D錯誤,故選:B3.下列函數(shù)中,既是偶函數(shù),又在SKIPIF1<0內(nèi)單調(diào)遞減的是(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】由于SKIPIF1<0,SKIPIF1<0,SKIPIF1<0的定義域是SKIPIF1<0,SKIPIF1<0,所以選項AD的函數(shù)是偶函數(shù),選項BC的函數(shù)不是偶函數(shù),排除BC,SKIPIF1<0上SKIPIF1<0是增函數(shù),SKIPIF1<0是減函數(shù),故選:D.4.判斷下列函數(shù)的奇偶性:(1)SKIPIF1<0;(2)SKIPIF1<0;(3)SKIPIF1<0;(4)SKIPIF1<0.【解析】(1)(1)∵函數(shù)SKIPIF1<0的定義域是SKIPIF1<0,關(guān)于坐標(biāo)原點不對稱∴SKIPIF1<0既不是奇函數(shù)也不是偶函數(shù).(2)∵函數(shù)SKIPIF1<0的定義域為SKIPIF1<0,關(guān)于坐標(biāo)原點對稱.又SKIPIF1<0,∴SKIPIF1<0為偶函數(shù).(3)∵函數(shù)SKIPIF1<0的定義域為SKIPIF1<0,關(guān)于坐標(biāo)原點對稱,SKIPIF1<0∴SKIPIF1<0既是奇函數(shù)也是偶函數(shù).(4)SKIPIF1<0的定義域為SKIPIF1<0.∵SKIPIF1<0SKIPIF1<0∴SKIPIF1<0,∴SKIPIF1<0為奇函數(shù).5.函數(shù)SKIPIF1<0.(1)判斷并證明函數(shù)SKIPIF1<0的單調(diào)性;(2)判斷并證明函數(shù)SKIPIF1<0的奇偶性;(3)解不等式SKIPIF1<0.【解析】(1)SKIPIF1<0,任取SKIPIF1<0,令SKIPIF1<0,則SKIPIF1<0,∵SKIPIF1<0則SKIPIF1<0,可得SKIPIF1<0,∴SKIPIF1<0即SKIPIF1<0,∴函數(shù)SKIPIF1<0在SKIPIF1<0上遞增.(2)SKIPIF1<0的定義域為SKIPIF1<0,∵SKIPIF1<0即SKIPIF1<0,∴SKIPIF1<0為定義在SKIPIF1<0上的奇函數(shù).(3)SKIPIF1<0即SKIPIF1<0,∵函數(shù)SKIPIF1<0在SKIPIF1<0上遞增,∴SKIPIF1<0即SKIPIF1<0或SKIPIF1<0.6.已知函數(shù)SKIPIF1<0對一切實數(shù)SKIPIF1<0都有SKIPIF1<0成立,且SKIPIF1<0.(1)分別求SKIPIF1<0和SKIPIF1<0的值;(2)判斷并證明函數(shù)SKIPIF1<0的奇偶性.【解析】(1)因為函數(shù)SKIPIF1<0對一切實數(shù)SKIPIF1<0都有SKIPIF1<0成立,SKIPIF1<0,所以當(dāng)SKIPIF1<0時SKIPIF1<0,即SKIPIF1<0,令SKIPIF1<0可得SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0(2)令SKIPIF1<0可得SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0,SKIPIF1<0,所以函數(shù)SKIPIF1<0是奇函數(shù).7.已知函數(shù)SKIPIF1<0滿足SKIPIF1<0.(1)求SKIPIF1<0的值;(2)求證:SKIPIF1<0;(3)若SKIPIF1<0,求SKIPIF1<0的值.【解析】(1)因為SKIPIF1<0,令SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0;(2)因為SKIPIF1<0,令SKIPIF1<0,則SKIPIF1<0,又SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0;(3)因為SKIPIF1<0且SKIPIF1<0,所以SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0,SKIPIF1<0;8.設(shè)函數(shù)SKIPIF1<0對任意SKIPIF1<0,都有SKIPIF1<0,且當(dāng)SKIPIF1<0時,SKIPIF1<0.(1)證明:SKIPIF1<0為奇函數(shù);(2)證明:SKIPIF1<0為減函數(shù),(3)若SKIPIF1<0,試求關(guān)于SKIPIF1<0的不等式SKIPIF1<0的解集.【解析】(1)證明:因為函數(shù)SKIPIF1<0對任意SKIPIF1<0,都有SKIPIF1<0,所以令SKIPIF1<0,則SKIPIF1<0,得SKIPIF1<0,令SKIPIF1<0,則有SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0,所以SKIPIF1<0為奇函數(shù)(2)證明:設(shè)SKIPIF1<0,則SKIPIF1<0,而SKIPIF1<0時,有SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0為減函數(shù)(3)因為SKIPIF1<0為奇函數(shù),SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,所以不等式SKIPIF1<0可轉(zhuǎn)化為SKIPIF1<0,因為SKIPIF1<0為減函數(shù),所以SKIPIF1<0,即SKIPIF1<0,解得SKIPIF1<0,所以不等式的解集為SKIPIF1<0專項突破二利用奇偶性求函數(shù)值或解析式1.已知SKIPIF1<0是定義在R上的奇函數(shù),且SKIPIF1<0時,SKIPIF1<0,則SKIPIF1<0(
)A.27 B.-27 C.54 D.-54【解析】由已知可得SKIPIF1<0,SKIPIF1<0,因此,SKIPIF1<0.故選:A.2.設(shè)SKIPIF1<0為奇函數(shù),且當(dāng)SKIPIF1<0時,SKIPIF1<0,則當(dāng)SKIPIF1<0時,SKIPIF1<0(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】設(shè)SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0,又SKIPIF1<0為奇函數(shù),所以SKIPIF1<0,所以當(dāng)SKIPIF1<0時,SKIPIF1<0.故選:B.3.已知函數(shù)SKIPIF1<0為偶函數(shù),則SKIPIF1<0(
)A.2 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【解析】SKIPIF1<0函數(shù)SKIPIF1<0為偶函數(shù),SKIPIF1<0當(dāng)SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,即SKIPIF1<0,又SKIPIF1<0,故SKIPIF1<0故選:A.4.已知SKIPIF1<0為奇函數(shù)且對任意SKIPIF1<0,SKIPIF1<0,若當(dāng)SKIPIF1<0時,SKIPIF1<0,則SKIPIF1<0(
)A.-1 B.0 C.1 D.2【解析】SKIPIF1<0是在R上的奇函數(shù),SKIPIF1<0,帶入SKIPIF1<0得SKIPIF1<0,即SKIPIF1<0SKIPIF1<0,SKIPIF1<0,SKIPIF1<0SKIPIF1<0,SKIPIF1<0,SKIPIF1<0關(guān)于直線SKIPIF1<0對稱,即原點SKIPIF1<0是SKIPIF1<0的對稱點,x=1是對稱軸,故函數(shù)SKIPIF1<0是周期為SKIPIF1<0的周期函數(shù),SKIPIF1<0,故選:A.5.已知SKIPIF1<0是R上的奇函數(shù),且當(dāng)SKIPIF1<0時,SKIPIF1<0,若SKIPIF1<0,則SKIPIF1<0(
)A.2020 B.SKIPIF1<0 C.4045 D.SKIPIF1<0【解析】因為SKIPIF1<0是R上的奇函數(shù),所以SKIPIF1<0,所以SKIPIF1<0,得SKIPIF1<0,所以當(dāng)SKIPIF1<0時,SKIPIF1<0,所以SKIPIF1<0.故選:D6.函數(shù)SKIPIF1<0滿足SKIPIF1<0,SKIPIF1<0,函數(shù)SKIPIF1<0的圖象關(guān)于點SKIPIF1<0對稱,則SKIPIF1<0(
)A.-8 B.0 C.-4 D.-2【解析】∵SKIPIF1<0關(guān)于SKIPIF1<0對稱,∴SKIPIF1<0關(guān)于SKIPIF1<0對稱,即SKIPIF1<0是奇函數(shù),令SKIPIF1<0得,SKIPIF1<0,即SKIPIF1<0SKIPIF1<0SKIPIF1<0,解得SKIPIF1<0SKIPIF1<0.∴SKIPIF1<0,即SKIPIF1<0,∴SKIPIF1<0,即函數(shù)的周期是4.∴SKIPIF1<0.故選:B.7.若定義在R上的偶函數(shù)SKIPIF1<0和奇函數(shù)SKIPIF1<0滿足SKIPIF1<0,則SKIPIF1<0的解析式為SKIPIF1<0___________.【解析】由題意得:SKIPIF1<0,即SKIPIF1<0①,SKIPIF1<0②,②-①得:SKIPIF1<0,解得:SKIPIF1<0.8.設(shè)函數(shù)SKIPIF1<0,若SKIPIF1<0,則SKIPIF1<0_____________.【解析】函數(shù)SKIPIF1<0的定義域為SKIPIF1<0,令SKIPIF1<0,則SKIPIF1<0,即SKIPIF1<0,所以SKIPIF1<0為奇函數(shù);因為SKIPIF1<0,所以SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0SKIPIF1<0.9.若已知函數(shù)f(x)=SKIPIF1<0是定義在(-1,1)上的奇函數(shù),且fSKIPIF1<0=SKIPIF1<0,則函數(shù)f(x)的解析式為________.【解析】∵f(x)=SKIPIF1<0是定義在(-1,1)上的奇函數(shù),∴f(0)=0,∴f(0)=SKIPIF1<0=0,∴b=0.即f(x)=SKIPIF1<0,又SKIPIF1<0,∴SKIPIF1<0.∴a=1,∴函數(shù)f(x)=SKIPIF1<0.,經(jīng)檢驗符合題意.10.已知SKIPIF1<0,且SKIPIF1<0,則SKIPIF1<0______.【解析】SKIPIF1<0,故SKIPIF1<0,所以SKIPIF1<011.已知函數(shù)SKIPIF1<0是定義在SKIPIF1<0上的偶函數(shù),且當(dāng)SKIPIF1<0時,SKIPIF1<0.(1)當(dāng)SKIPIF1<0時,求SKIPIF1<0的解析式;(2)若SKIPIF1<0,求SKIPIF1<0的值.【解析】(1)(1)當(dāng)SKIPIF1<0時,SKIPIF1<0,所以SKIPIF1<0,又SKIPIF1<0是偶函數(shù),∴SKIPIF1<0,∴SKIPIF1<0,所以當(dāng)SKIPIF1<0時,SKIPIF1<0;(2)當(dāng)SKIPIF1<0時,當(dāng)SKIPIF1<0時,SKIPIF1<0,即SKIPIF1<0,解得SKIPIF1<0(SKIPIF1<0舍去),當(dāng)SKIPIF1<0時,SKIPIF1<0,∴.SKIPIF1<0(SKIPIF1<0舍去),綜上,SKIPIF1<0或SKIPIF1<0.12.若奇函數(shù)SKIPIF1<0在定義域SKIPIF1<0上是減函數(shù),若SKIPIF1<0時,SKIPIF1<0,(1)求SKIPIF1<0的解析式;(2)求滿足SKIPIF1<0的實數(shù)m的取值范圍【解析】(1)因為SKIPIF1<0是定義域SKIPIF1<0上的奇函數(shù),所以對于任意SKIPIF1<0,則SKIPIF1<0,且SKIPIF1<0.設(shè)SKIPIF1<0,則SKIPIF1<0,由已知得SKIPIF1<0,而SKIPIF1<0滿足上式,所以SKIPIF1<0.(2)由于SKIPIF1<0在定義域SKIPIF1<0上是減函數(shù),且為奇函數(shù),所以SKIPIF1<0,即SKIPIF1<0,所以有SKIPIF1<0,所以m的取值范圍為SKIPIF1<0.專項突破三由奇偶性解不等式1.已知函數(shù)SKIPIF1<0,則關(guān)于x的不等式SKIPIF1<0的解集為(
)A.SKIPIF1<0 B.(-1,2)C.SKIPIF1<0 D.SKIPIF1<0【解析】SKIPIF1<0的定義域是SKIPIF1<0,SKIPIF1<0,故SKIPIF1<0是偶函數(shù),又SKIPIF1<0,令SKIPIF1<0,當(dāng)且僅當(dāng)SKIPIF1<0時取等號,SKIPIF1<0在SKIPIF1<0單調(diào)遞增,而SKIPIF1<0,SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0遞減,SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0遞增,故由SKIPIF1<0得SKIPIF1<0,解得SKIPIF1<0,即不等式SKIPIF1<0的解集為SKIPIF1<0,故選:SKIPIF1<0.2.設(shè)SKIPIF1<0是定義在R上的奇函數(shù),且當(dāng)SKIPIF1<0時,SKIPIF1<0,則SKIPIF1<0的解集為(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】SKIPIF1<0即SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0,即SKIPIF1<0,可得SKIPIF1<0,當(dāng)SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0,因此SKIPIF1<0即SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0,綜上,不等式的解集為SKIPIF1<0或SKIPIF1<0.故選:C.3.已知函數(shù)SKIPIF1<0為偶函數(shù),且當(dāng)SKIPIF1<0時,SKIPIF1<0,則不等式SKIPIF1<0的解集為(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】當(dāng)SKIPIF1<0時,SKIPIF1<0,所以SKIPIF1<0,因為SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0,所以函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞增,又因為函數(shù)SKIPIF1<0為SKIPIF1<0上的偶函數(shù),所以函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞減.則不等式SKIPIF1<0,即SKIPIF1<0等價于SKIPIF1<0,解得SKIPIF1<0或SKIPIF1<0.故選:D.4.函數(shù)SKIPIF1<0在SKIPIF1<0單調(diào)遞增,且為奇函數(shù),若SKIPIF1<0,則滿足SKIPIF1<0的SKIPIF1<0的取值范圍是(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【解析】SKIPIF1<0為奇函數(shù),SKIPIF1<0,又SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0可化為:SKIPIF1<0,SKIPIF1<0在SKIPIF1<0單調(diào)遞增,SKIPIF1<0,解得:SKIPIF1<0,SKIPIF1<0SKIPIF1<0的取值范圍為SKIPIF1<0.故選:C.5.已知函數(shù)SKIPIF1<0是定義在R上的偶函數(shù),且在區(qū)間SKIPIF1<0上是減函數(shù),SKIPIF1<0,則不等式SKIPIF1<0的解集為(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】因為函數(shù)SKIPIF1<0是定義在R上的偶函數(shù),且在區(qū)間SKIPIF1<0上是減函數(shù),所以,函數(shù)SKIPIF1<0在SKIPIF1<0上是增函數(shù),所以SKIPIF1<0,即有SKIPIF1<0,所以SKIPIF1<0或SKIPIF1<0,解得SKIPIF1<0或SKIPIF1<0.故選:D.6.設(shè)SKIPIF1<0是奇函數(shù),且在SKIPIF1<0上是增函數(shù),又SKIPIF1<0,則SKIPIF1<0的解集是(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】SKIPIF1<0函數(shù)SKIPIF1<0為奇函數(shù),SKIPIF1<0,SKIPIF1<0函數(shù)在SKIPIF1<0上是增函數(shù),SKIPIF1<0函數(shù)在SKIPIF1<0上是增函數(shù),SKIPIF1<0對于SKIPIF1<0,需SKIPIF1<0,解得SKIPIF1<0,或SKIPIF1<0,解得SKIPIF1<0,SKIPIF1<0的范圍是SKIPIF1<0.故選:C.7.已知函數(shù)SKIPIF1<0,若SKIPIF1<0,則實數(shù)SKIPIF1<0的取值范圍是(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】由題意,函數(shù)SKIPIF1<0,根據(jù)二次函數(shù)的性質(zhì),作出函數(shù)SKIPIF1<0的圖象,如圖所示,結(jié)合圖象,可知函數(shù)SKIPIF1<0的圖象關(guān)于SKIPIF1<0軸對稱,即函數(shù)SKIPIF1<0為偶函數(shù),所以SKIPIF1<0,即SKIPIF1<0,當(dāng)SKIPIF1<0時,不等式SKIPIF1<0,即為SKIPIF1<0,解得SKIPIF1<0;當(dāng)SKIPIF1<0時,不等式SKIPIF1<0,即為SKIPIF1<0,解得SKIPIF1<0,綜上可得,實數(shù)SKIPIF1<0的取值范圍是SKIPIF1<0.故選:C.8.若函數(shù)SKIPIF1<0是奇函數(shù),且在SKIPIF1<0上是減函數(shù),又SKIPIF1<0,則SKIPIF1<0的解集是(
)A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【解析】:SKIPIF1<0在SKIPIF1<0上是減函數(shù)且SKIPIF1<0,SKIPIF1<0當(dāng)SKIPIF1<0時,SKIPIF1<0,當(dāng)SKIPIF1<0時,SKIPIF1<0.又SKIPIF1<0是奇函數(shù),SKIPIF1<0由函數(shù)圖象的對稱性知:當(dāng)SKIPIF1<0時,SKIPIF1<0,當(dāng)SKIPIF1<0時,SKIPIF1<0.SKIPIF1<0不等式SKIPIF1<0,等價于SKIPIF1<0或SKIPIF1<0,SKIPIF1<0或SKIPIF1<0,即不等式的解集為SKIPIF1<0.故選:C.9.已知函數(shù)SKIPIF1<0,則SKIPIF1<0的解集為____________.【解析】由題意知,定義域為R,SKIPIF1<0,故SKIPIF1<0為奇函數(shù),又SKIPIF1<0,故SKIPIF1<0為增函數(shù),由SKIPIF1<0可得SKIPIF1<0,即SKIPIF1<0,解得SKIPIF1<0.故答案為:SKIPIF1<0.10.已知定義域為SKIPIF1<0的函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞增,且SKIPIF1<0,若SKIPIF1<0,則不等式SKIPIF1<0的解集為___________.【解析】因為定義域為SKIPIF1<0的函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞增,且SKIPIF1<0,所以函數(shù)SKIPIF1<0在SKIPIF1<0上為奇函數(shù),且在SKIPIF1<0上單調(diào)遞增,又SKIPIF1<0,所以SKIPIF1<0,又不等式SKIPIF1<0等價于SKIPIF1<0,所以SKIPIF1<0,解得SKIPIF1<0,所以不等式SKIPIF1<0的解集為SKIPIF1<0.11.已知SKIPIF1<0是定義在R上的偶函數(shù),其導(dǎo)函數(shù)為SKIPIF1<0.若SKIPIF1<0時,SKIPIF1<0,則不等式SKIPIF1<0SKIPIF1<0的解集為__________.【解析】SKIPIF1<0SKIPIF1<0,∴SKIPIF1<0在SKIPIF1<0上是增函數(shù),且SKIPIF1<0為偶函數(shù),由SKIPIF1<0SKIPIF1<0SKIPIF1<0,∴SKIPIF1<0,解得SKIPIF1<0,∴解集為SKIPIF1<012.已知函數(shù)SKIPIF1<0是定義在R上的奇函數(shù),當(dāng)SKIPIF1<0時,SKIPIF1<0.(1)求函數(shù)SKIPIF1<0在SKIPIF1<0上的解析式;(2)求不等式SKIPIF1<0的解集.【解析】(1)當(dāng)SKIPIF1<0時,SKIPIF1<0,SKIPIF1<0.所以函數(shù)SKIPIF1<0在SKIPIF1<0上的解析式為SKIPIF1<0.(2)當(dāng)SKIPIF1<0時,SKIPIF1<0為增函數(shù),所以SKIPIF1<0在SKIPIF1<0上為增函數(shù).由SKIPIF1<0得SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,所以不等式SKIPIF1<0的解集為SKIPIF1<0.專項突破四利用奇偶性求參1.若函數(shù)SKIPIF1<0為奇函數(shù),則實數(shù)SKIPIF1<0的值為(
)A.1 B.2 C.SKIPIF1<0 D.SKIPIF1<0【解析】由SKIPIF1<0為奇函數(shù),所以SKIPIF1<0,所以SKIPIF1<0,可得SKIPIF1<0,解得SKIPIF1<0,當(dāng)SKIPIF1<0時,SKIPIF1<0的定義域為SKIPIF1<0,符合題意,當(dāng)SKIPIF1<0時,SKIPIF1<0的定義域為SKIPIF1<0符合題意,故選:D2.已知函數(shù)SKIPIF1<0是偶函數(shù),則SKIPIF1<0的值是(
)A.SKIPIF1<0 B.SKIPIF1<0 C.1 D.2【解析】函數(shù)的定義域為SKIPIF1<0,因為函數(shù)SKIPIF1<0是偶函數(shù),所以SKIPIF1<0,所以SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0,得SKIPIF1<0,故選:A3.若函數(shù)SKIPIF1<0為偶函數(shù),則實數(shù)SKIPIF1<0(
)A.SKIPIF1<0 B.3 C.SKIPIF1<0 D.9【解析】由題意,函數(shù)SKIPIF1<0為偶函數(shù),因為函數(shù)SKIPIF1<0為奇函數(shù),所以SKIPIF1<0為奇函數(shù),由SKIPIF1<0,可得SKIPIF1<0,解得SKIPIF1<0.故選:D.4.若函數(shù)SKIPIF1<0為偶函數(shù),設(shè)SKIPIF1<0,則SKIPIF1<0的大小關(guān)系為(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【解析】函數(shù)SKIPIF1<0為偶函數(shù),SKIPIF1<0恒成立,SKIPIF1<0恒成立,即SKIPIF1<0,SKIPIF1<0在SKIPIF1<0單調(diào)遞增,所以SKIPIF1<0,SKIPIF1<0,SKIPIF1<0所以SKIPIF1<0.故選:D5.已知函數(shù)SKIPIF1<0為偶函數(shù),則SKIPIF1<0______.【解析】由題設(shè),SKIPIF1<0,所以SKIPIF1<0.6.函數(shù)SKIPIF1<0是偶函數(shù),且它的值域為SKIPIF1<0,則SKIPIF1<0__________.【解析】SKIPIF1<0為偶函數(shù),所以SKIPIF1<0,即SKIPIF1<0或SKIPIF1<0,當(dāng)SKIPIF1<0時,SKIPIF1<0值域不符合SKIPIF1<0,所以SKIPIF1<0不成立;當(dāng)SKIPIF1<0時,SKIPIF1<0,若值域為SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0.7.若函數(shù)SKIPIF1<0在SKIPIF1<0上為奇函數(shù),則SKIPIF1<0___________.【解析】因為函數(shù)SKIPIF1<0在SKIPIF1<0上為奇函數(shù),所以SKIPIF1<0,得SKIPIF1<0,又SKIPIF1<0,即SKIPIF1<0,即SKIPIF1<0恒成立,所以SKIPIF1<0,所以SKIPIF1<0.8.已知SKIPIF1<0是奇函數(shù),且當(dāng)SKIPIF1<0時,SKIPIF1<0.若SKIPIF1<0,則SKIPIF1<0______.【解析】由題設(shè)知:SKIPIF1<0,又SKIPIF1<0是奇函數(shù),所以SKIPIF1<0,可得SKIPIF1<0.9.已知函數(shù)SKIPIF1<0是偶函數(shù),則實數(shù)SKIPIF1<0的值為______.【解析】由題意知:定義域為R,函數(shù)SKIPIF1<0是偶函數(shù),則SKIPIF1<0,即SKIPIF1<0,化簡得SKIPIF1<0,解得SKIPIF1<0.10.已知函數(shù)SKIPIF1<0為R上的偶函數(shù),則實數(shù)SKIPIF1<0___________.【解析】由偶函數(shù)得SKIPIF1<0,即SKIPIF1<0對SKIPIF1<0恒成立整理得SKIPIF1<0,故SKIPIF1<011.已知函數(shù)SKIPIF1<0是定義域在R上的奇函數(shù),且SKIPIF1<0.(1)求實數(shù)a,b的值;(2)解關(guān)于x的不等式:SKIPIF1<0.【解析】(1)因為SKIPIF1<0是定義域在R上的奇函數(shù),故可得SKIPIF1<0,即SKIPIF1<0;SKIPIF1<0又SKIPIF1<0,故可得SKIPIF1<0,即SKIPIF1<0;解得SKIPIF1<0.(2)由(1)知SKIPIF1<0,下證SKIPIF1<0是SKIPIF1<0上的單調(diào)增函數(shù).令SKIPIF1<0,故可得SKIPIF1<0,因為SKIPIF1<0是SKIPIF1<0上的單調(diào)增函數(shù),故可得SKIPIF1<0,又SKIPIF1<0,故SKIPIF1<0,則SKIPIF1<0,即證SKIPIF1<0為SKIPIF1<0上的單調(diào)增函數(shù),又SKIPIF1<0為奇函數(shù),故SKIPIF1<0,即SKIPIF1<0,SKIPIF1<0,也即SKIPIF1<0SKIPIF1<0SKIPIF1<0,又SKIPIF1<0為SKIPIF1<0上的單調(diào)減函數(shù),故可得SKIPIF1<0,解得SKIPIF1<0.故不等式的解集為:SKIPIF1<0.12.已知定義
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