新高考數(shù)學(xué)一輪復(fù)習(xí)講練測(cè)專題5.3三角函數(shù)的圖象與性質(zhì)(練)解析版_第1頁(yè)
新高考數(shù)學(xué)一輪復(fù)習(xí)講練測(cè)專題5.3三角函數(shù)的圖象與性質(zhì)(練)解析版_第2頁(yè)
新高考數(shù)學(xué)一輪復(fù)習(xí)講練測(cè)專題5.3三角函數(shù)的圖象與性質(zhì)(練)解析版_第3頁(yè)
新高考數(shù)學(xué)一輪復(fù)習(xí)講練測(cè)專題5.3三角函數(shù)的圖象與性質(zhì)(練)解析版_第4頁(yè)
新高考數(shù)學(xué)一輪復(fù)習(xí)講練測(cè)專題5.3三角函數(shù)的圖象與性質(zhì)(練)解析版_第5頁(yè)
已閱讀5頁(yè),還剩13頁(yè)未讀, 繼續(xù)免費(fèi)閱讀

下載本文檔

版權(quán)說(shuō)明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)

文檔簡(jiǎn)介

專題5.3三角函數(shù)的圖象與性質(zhì)練基礎(chǔ)練基礎(chǔ)1.(2021·北京市大興區(qū)精華培訓(xùn)學(xué)校高三三模)下列函數(shù)中,既是奇函數(shù)又以SKIPIF1<0為最小正周期的函數(shù)是()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B【解析】由三角函數(shù)的奇偶性和周期性判斷即可得出答案.【詳解】解:A選項(xiàng):SKIPIF1<0是周期為SKIPIF1<0的偶函數(shù),故A不正確;B選項(xiàng):SKIPIF1<0是周期為SKIPIF1<0的奇函數(shù),故B正確;C選項(xiàng):SKIPIF1<0,周期為SKIPIF1<0且非奇非偶函數(shù),故C不正確;D選項(xiàng):SKIPIF1<0是周期為SKIPIF1<0的奇函數(shù),故D不正確.故選:B.2.(2021·海南高三其他模擬)下列函數(shù)中,既是偶函數(shù)又存在零點(diǎn)的是()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】D【解析】根據(jù)題意,依次分析選項(xiàng)中函數(shù)的奇偶性以及是否存在零點(diǎn),綜合即可得答案.【詳解】解:根據(jù)題意,依次分析選項(xiàng):對(duì)于SKIPIF1<0,SKIPIF1<0,為對(duì)數(shù)函數(shù),不是奇函數(shù),不符合題意,對(duì)于SKIPIF1<0,SKIPIF1<0,為二次函數(shù),是偶函數(shù),但不存在零點(diǎn),不符合題意,對(duì)于SKIPIF1<0,SKIPIF1<0,為正弦函數(shù),是奇函數(shù),不符合題意,對(duì)于SKIPIF1<0,SKIPIF1<0,為余弦函數(shù),既是偶函數(shù)又存在零點(diǎn),符合題意,故選:SKIPIF1<0.3.(2021·浙江高三其他模擬)函數(shù)y=SKIPIF1<0在[-2,2]上的圖像可能是()A. B.C. D.【答案】B【解析】利用同角三角函數(shù)的商數(shù)關(guān)系并注意利用正切函數(shù)的性質(zhì)求得函數(shù)的定義域,可以化簡(jiǎn)得到SKIPIF1<0,考察當(dāng)SKIPIF1<0趨近于0時(shí),函數(shù)的變化趨勢(shì),可以排除A,考察端點(diǎn)值的正負(fù)可以評(píng)出CD.【詳解】SKIPIF1<0,當(dāng)SKIPIF1<0趨近于0時(shí),函數(shù)值趨近于SKIPIF1<0,故排除A;SKIPIF1<0,故排除CD,故選:B4.(2021·全國(guó)高三其他模擬(理))函數(shù)y=tan(3x+SKIPIF1<0)的一個(gè)對(duì)稱中心是()A.(0,0) B.(SKIPIF1<0,0)C.(SKIPIF1<0,0) D.以上選項(xiàng)都不對(duì)【答案】C【解析】根據(jù)正切函數(shù)y=tanx圖象的對(duì)稱中心是(SKIPIF1<0,0)求出函數(shù)y=tan(3x+SKIPIF1<0)圖象的對(duì)稱中心,即可得到選項(xiàng).【詳解】解:因?yàn)檎泻瘮?shù)y=tanx圖象的對(duì)稱中心是(SKIPIF1<0,0),k∈Z;令3x+SKIPIF1<0=SKIPIF1<0,解得SKIPIF1<0,k∈Z;所以函數(shù)y=tan(3x+SKIPIF1<0)的圖象的對(duì)稱中心為(SKIPIF1<0,0),k∈Z;當(dāng)k=3時(shí),C正確,故選:C.5.(2019年高考全國(guó)Ⅱ卷文)若x1=,x2=是函數(shù)f(x)=(>0)兩個(gè)相鄰的極值點(diǎn),則=()A.2 B. C.1 D.【答案】A【解析】由題意知,的周期,解得.故選A.6.(2021·臨川一中實(shí)驗(yàn)學(xué)校高三其他模擬(文))若函數(shù)SKIPIF1<0的圖象在區(qū)間SKIPIF1<0上只有一個(gè)對(duì)稱中心,則SKIPIF1<0的取范圍為()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】A【解析】根據(jù)題意可得SKIPIF1<0,即可求出.【詳解】由題可知,SKIPIF1<0在SKIPIF1<0上只有一個(gè)零點(diǎn),又SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0.故選:A.7.(2019年高考北京卷文)設(shè)函數(shù)f(x)=cosx+bsinx(b為常數(shù)),則“b=0”是“f(x)為偶函數(shù)”的()A.充分而不必要條件 B.必要而不充分條件

C.充分必要條件 D.既不充分也不必要條件【答案】C【解析】時(shí),,為偶函數(shù);為偶函數(shù)時(shí),對(duì)任意的恒成立,即,,得對(duì)任意的恒成立,從而.從而“”是“為偶函數(shù)”的充分必要條件,故選C.8.(2021·青海西寧市·高三二模(文))函數(shù)SKIPIF1<0圖象的一個(gè)對(duì)稱中心為()A.SKIPIF1<0 B.SKIPIF1<0C.SKIPIF1<0 D.SKIPIF1<0【答案】D【解析】根據(jù)余弦函數(shù)的對(duì)稱中心整體代換求解即可.【詳解】令SKIPIF1<0,可得SKIPIF1<0.所以當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,故SKIPIF1<0滿足條件,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,故SKIPIF1<0滿足條件;故選:D9.(2021·全國(guó)高一專題練習(xí))設(shè)函數(shù)SKIPIF1<0,則下列結(jié)論錯(cuò)誤的是()A.SKIPIF1<0的最小正周期為SKIPIF1<0 B.SKIPIF1<0的圖象關(guān)于直線SKIPIF1<0對(duì)稱C.SKIPIF1<0在SKIPIF1<0單調(diào)遞減 D.SKIPIF1<0的一個(gè)零點(diǎn)為SKIPIF1<0【答案】C【解析】根據(jù)解析式結(jié)合余弦函數(shù)的性質(zhì)依次判斷每個(gè)選項(xiàng)的正誤即可.【詳解】SKIPIF1<0函數(shù)SKIPIF1<0,SKIPIF1<0的最小正周期為SKIPIF1<0,故A正確;SKIPIF1<0SKIPIF1<0,SKIPIF1<0SKIPIF1<0的圖象關(guān)于直線SKIPIF1<0對(duì)稱,故B正確;當(dāng)SKIPIF1<0SKIPIF1<0時(shí),SKIPIF1<0,SKIPIF1<0沒有單調(diào)性,故C錯(cuò)誤;SKIPIF1<0SKIPIF1<0,SKIPIF1<0SKIPIF1<0的一個(gè)零點(diǎn)為SKIPIF1<0,故D正確.綜上,錯(cuò)誤的選項(xiàng)為C.故選:C.10.(2017·全國(guó)高考真題(理))函數(shù)fx=s【答案】1【解析】化簡(jiǎn)三角函數(shù)的解析式,則fx=1?cos2x+3cosx?34=?練提升TIDHNEG練提升TIDHNEG1.(2021·河南高二月考(文))已知函數(shù)SKIPIF1<0的相鄰的兩個(gè)零點(diǎn)之間的距離是SKIPIF1<0,且直線SKIPIF1<0是SKIPIF1<0圖象的一條對(duì)稱軸,則SKIPIF1<0()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】D【解析】由相鄰兩個(gè)零點(diǎn)的距離確定周期求出SKIPIF1<0,再由對(duì)稱軸確定SKIPIF1<0,代入SKIPIF1<0可求出結(jié)果.【詳解】解:因?yàn)橄噜彽膬蓚€(gè)零點(diǎn)之間的距離是SKIPIF1<0,所以SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0,又SKIPIF1<0,且SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0,則SKIPIF1<0.故選:D.2.(2020·山東濰坊?高一期末)若函數(shù)的最小正周期為,則()A. B.C. D.【答案】C【解析】由題意,函數(shù)的最小正周期為,可得,解得,即,令,即,當(dāng)時(shí),,即函數(shù)在上單調(diào)遞增,又由,又由,所以.故選:C.3.(2021·廣東佛山市·高三二模)設(shè)SKIPIF1<0,則“SKIPIF1<0”是“SKIPIF1<0”的()A.充分不必要條件 B.必要不充分條件C.充要條件 D.既不充分也不必要條件【答案】A【解析】由條件即SKIPIF1<0,由SKIPIF1<0,得SKIPIF1<0;反之不成立,可舉反例.再由充分必要條件的判定得答案.【詳解】由SKIPIF1<0,則SKIPIF1<0,即SKIPIF1<0所以當(dāng)SKIPIF1<0時(shí),由正弦函數(shù)SKIPIF1<0的單調(diào)性可得SKIPIF1<0,即由SKIPIF1<0可以得到SKIPIF1<0.反之不成立,例如當(dāng)SKIPIF1<0時(shí),也有SKIPIF1<0成立,但SKIPIF1<0不成立.故“SKIPIF1<0”是“SKIPIF1<0”的充分不必要條件故選:A4.(2021·四川省華鎣中學(xué)高三其他模擬(理))已知函數(shù)SKIPIF1<0的最大值為2,其圖象相鄰兩條對(duì)稱軸之間的距離為SKIPIF1<0且SKIPIF1<0的圖象關(guān)于點(diǎn)SKIPIF1<0對(duì)稱,則下列判斷不正確的是()A.要得到函數(shù)SKIPIF1<0的圖象,只需將SKIPIF1<0的圖象向右平移SKIPIF1<0個(gè)單位B.函數(shù)SKIPIF1<0的圖象關(guān)于直線SKIPIF1<0對(duì)稱C.SKIPIF1<0時(shí),函數(shù)SKIPIF1<0的最小值為SKIPIF1<0D.函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞減【答案】C【解析】根據(jù)最大值為2,可得A,根據(jù)正弦型函數(shù)的周期性,可求得SKIPIF1<0,根據(jù)對(duì)稱性,可求得SKIPIF1<0,即可得SKIPIF1<0解析式,根據(jù)正弦型函數(shù)的單調(diào)性、值域的求法,逐一分析選項(xiàng),即可得答案.【詳解】由題意得A=2,因?yàn)槠鋱D象相鄰兩條對(duì)稱軸之間的距離為SKIPIF1<0,所以SKIPIF1<0,可得SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,因?yàn)镾KIPIF1<0為對(duì)稱中心,所以SKIPIF1<0,因?yàn)镾KIPIF1<0,令k=0,可得SKIPIF1<0,所以SKIPIF1<0.對(duì)于A:將SKIPIF1<0的圖象向右平移SKIPIF1<0個(gè)單位,可得SKIPIF1<0,故A正確;對(duì)于B:令SKIPIF1<0,解得SKIPIF1<0,令k=1,可得SKIPIF1<0,所以函數(shù)SKIPIF1<0的圖象關(guān)于直線SKIPIF1<0對(duì)稱,故B正確;對(duì)于C:因?yàn)镾KIPIF1<0,所以SKIPIF1<0,所以當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,故C錯(cuò)誤;對(duì)于D:令SKIPIF1<0,解得SKIPIF1<0,令k=0,可得一個(gè)單調(diào)減區(qū)間為SKIPIF1<0,因?yàn)镾KIPIF1<0,所以函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞減,故D正確.故選:C5.(2021·玉林市第十一中學(xué)高三其他模擬(文))已知函數(shù)SKIPIF1<0的圖象向右平移SKIPIF1<0個(gè)單位長(zhǎng)度得y=g(x)的圖象,若函數(shù)g(x)的圖象與直線SKIPIF1<0在SKIPIF1<0上恰有兩個(gè)交點(diǎn),則a的取值范圍是()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B【解析】由函數(shù)的平移可得SKIPIF1<0,結(jié)合三角函數(shù)的圖象與性質(zhì)可得SKIPIF1<0滿足的不等式,即可得解.【詳解】由題意,SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,因?yàn)楹瘮?shù)g(x)的圖象與直線SKIPIF1<0在SKIPIF1<0上恰有兩個(gè)交點(diǎn),則SKIPIF1<0或SKIPIF1<0,SKIPIF1<0,又SKIPIF1<0,所以SKIPIF1<0.故選:B.6.(2020·北京四中高三其他模擬)函數(shù)SKIPIF1<0的部分圖象如圖所示,則SKIPIF1<0()A.6 B.5 C.4 D.3【答案】A【解析】根據(jù)正切函數(shù)的圖象求出A、B兩點(diǎn)的坐標(biāo),再求出向量的坐標(biāo),根據(jù)向量數(shù)量積的坐標(biāo)運(yùn)算求出結(jié)果.【詳解】由圖象得,令SKIPIF1<0=0,即SKIPIF1<0=kπ,SKIPIF1<0k=0時(shí)解得x=2,令SKIPIF1<0=1,即SKIPIF1<0,解得x=3,∴A(2,0),B(3,1),∴SKIPIF1<0,∴SKIPIF1<0.故選:A.7.(2020·全國(guó)高三其他模擬(文))若函數(shù)SKIPIF1<0圖象上的相鄰一個(gè)最高點(diǎn)和一個(gè)最低點(diǎn)恰好都在圓SKIPIF1<0上,則SKIPIF1<0()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】A【解析】首先由題意判斷該正弦型函數(shù)的大概圖象及相鄰最高點(diǎn)和最低點(diǎn)與圓的交點(diǎn)情況.從而解得n的取值,再代入SKIPIF1<0求解.【詳解】解:設(shè)兩交點(diǎn)坐標(biāo)分別為SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0,SKIPIF1<0,又函數(shù)SKIPIF1<0為奇函數(shù),∴SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),函數(shù)取得最大值SKIPIF1<0,∴SKIPIF1<0,SKIPIF1<0,由題,函數(shù)SKIPIF1<0圖象上的相鄰一個(gè)最高點(diǎn)和一個(gè)最低點(diǎn)恰好都在圓SKIPIF1<0上,∴SKIPIF1<0,則SKIPIF1<0.故選:A.8.【多選題】(2021·全國(guó)高三其他模擬)已知函數(shù)SKIPIF1<0圖象的一條對(duì)稱軸為SKIPIF1<0,SKIPIF1<0,且SKIPIF1<0在SKIPIF1<0內(nèi)單調(diào)遞減,則以下說(shuō)法正確的是()A.SKIPIF1<0是其中一個(gè)對(duì)稱中心 B.SKIPIF1<0C.SKIPIF1<0在SKIPIF1<0單増 D.SKIPIF1<0【答案】AD【解析】先根據(jù)條件求解函數(shù)的解析式,然后根據(jù)選項(xiàng)驗(yàn)證可得答案.【詳解】∵f(x)關(guān)SKIPIF1<0對(duì)稱,SKIPIF1<0,f(x)在SKIPIF1<0單調(diào)遞減,SKIPIF1<0,B錯(cuò)誤;SKIPIF1<0令SKIPIF1<0,可得SKIPIF1<0當(dāng)SKIPIF1<0時(shí),SKIPIF1<0即SKIPIF1<0關(guān)于SKIPIF1<0對(duì)稱,A正確;令SKIPIF1<0得SKIPIF1<0∴SKIPIF1<0在SKIPIF1<0單調(diào)遞増,即C錯(cuò)誤;SKIPIF1<0,D正確,故選:AD.9.【多選題】(2021·重慶市蜀都中學(xué)校高三月考)已知函數(shù)SKIPIF1<0滿足SKIPIF1<0,有SKIPIF1<0,且SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,則下列說(shuō)法正確的是()A.SKIPIF1<0B.SKIPIF1<0時(shí),SKIPIF1<0單調(diào)遞增C.SKIPIF1<0關(guān)于點(diǎn)SKIPIF1<0對(duì)稱D.SKIPIF1<0時(shí),方程SKIPIF1<0的所有根的和為SKIPIF1<0【答案】CD【解析】利用已知條件可知SKIPIF1<0在SKIPIF1<0上為奇函數(shù)且單調(diào)遞減,關(guān)于SKIPIF1<0、SKIPIF1<0,SKIPIF1<0對(duì)稱,且周期為4,即可判斷各選項(xiàng)的正誤.【詳解】由題設(shè)知:SKIPIF1<0,故SKIPIF1<0在SKIPIF1<0上為奇函數(shù)且單調(diào)遞減,又SKIPIF1<0,即關(guān)于SKIPIF1<0、SKIPIF1<0,SKIPIF1<0對(duì)稱,且最小周期為4,A:SKIPIF1<0,錯(cuò)誤;B:SKIPIF1<0等價(jià)于SKIPIF1<0,由上易知:SKIPIF1<0上遞減,SKIPIF1<0上遞增,故SKIPIF1<0不單調(diào),錯(cuò)誤;C:由上知:SKIPIF1<0關(guān)于SKIPIF1<0對(duì)稱且SKIPIF1<0,所以SKIPIF1<0關(guān)于SKIPIF1<0對(duì)稱,正確;D:由題意,只需確定SKIPIF1<0與SKIPIF1<0在SKIPIF1<0的交點(diǎn),判斷交點(diǎn)橫坐標(biāo)的對(duì)稱情況即可求和,如下圖示,∴共有6個(gè)交點(diǎn)且關(guān)于SKIPIF1<0對(duì)稱,則SKIPIF1<0,∴所有根的和為SKIPIF1<0,正確.故選:CD10.(2021·浙江杭州市·杭州高級(jí)中學(xué)高三其他模擬)設(shè)函數(shù)SKIPIF1<0在SKIPIF1<0上的最大值為SKIPIF1<0,最小值為SKIPIF1<0,則SKIPIF1<0在SKIPIF1<0上最大值為________.【答案】1【解析】依題意可得函數(shù)在SKIPIF1<0上單調(diào)遞減,則SKIPIF1<0,所以SKIPIF1<0,即可求出函數(shù)的最大值;【詳解】解:函數(shù)SKIPIF1<0的周期為6,函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞減,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0SKIPIF1<0因?yàn)镾KIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0所以SKIPIF1<0當(dāng)SKIPIF1<0時(shí)取最大值1故答案為:SKIPIF1<0練真題TIDHNEG練真題TIDHNEG1.(2021·全國(guó)高考真題(理))已知命題SKIPIF1<0﹔命題SKIPIF1<0﹐SKIPIF1<0,則下列命題中為真命題的是()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】A【解析】由正弦函數(shù)的有界性確定命題SKIPIF1<0的真假性,由指數(shù)函數(shù)的知識(shí)確定命題SKIPIF1<0的真假性,由此確定正確選項(xiàng).【詳解】由于SKIPIF1<0,所以命題SKIPIF1<0為真命題;由于SKIPIF1<0,所以SKIPIF1<0,所以命題SKIPIF1<0為真命題;所以SKIPIF1<0為真命題,SKIPIF1<0、SKIPIF1<0、SKIPIF1<0為假命題.故選:A.2.(2021·全國(guó)高考真題)下列區(qū)間中,函數(shù)SKIPIF1<0單調(diào)遞增的區(qū)間是()A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】A【解析】解不等式SKIPIF1<0,利用賦值法可得出結(jié)論.【詳解】因?yàn)楹瘮?shù)SKIPIF1<0的單調(diào)遞增區(qū)間為SKIPIF1<0,對(duì)于函數(shù)SKIPIF1<0,由SKIPIF1<0,解得SKIPIF1<0,取SKIPIF1<0,可得函數(shù)SKIPIF1<0的一個(gè)單調(diào)遞增區(qū)間為SKIPIF1<0,則SKIPIF1<0,SKIPIF1<0,A選項(xiàng)滿足條件,B不滿足條件;取SKIPIF1<0,可得函數(shù)SKIPIF1<0的一個(gè)單調(diào)遞增區(qū)間為SKIPIF1<0,SKIPIF1<0且SKIPIF1<0,SKIPIF1<0,CD選項(xiàng)均不滿足條件.故選:A.3.(2019年

溫馨提示

  • 1. 本站所有資源如無(wú)特殊說(shuō)明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
  • 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
  • 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁(yè)內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
  • 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
  • 5. 人人文庫(kù)網(wǎng)僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
  • 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
  • 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。

最新文檔

評(píng)論

0/150

提交評(píng)論