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第一篇熱點(diǎn)、難點(diǎn)突破篇專題18圓錐曲線的幾何性質(zhì)問題(練)【對點(diǎn)演練】一、單選題1.(2022秋·福建寧德·高三??计谀┮阎獟佄锞€SKIPIF1<0的焦點(diǎn)為F,拋物線上一點(diǎn)SKIPIF1<0滿足SKIPIF1<0,則SKIPIF1<0(
)A.1 B.2 C.SKIPIF1<0 D.SKIPIF1<0【答案】A【分析】根據(jù)拋物線焦半徑公式列出方程,求出SKIPIF1<0的值.【詳解】由拋物線定義知:SKIPIF1<0,所以SKIPIF1<0,解得:SKIPIF1<0.故選:A2.(2023秋·貴州銅仁·高三統(tǒng)考期末)已知拋物線SKIPIF1<0的焦點(diǎn)為SKIPIF1<0,點(diǎn)SKIPIF1<0是拋物線SKIPIF1<0上不同兩點(diǎn),且SKIPIF1<0中點(diǎn)的橫坐標(biāo)為SKIPIF1<0,則SKIPIF1<0(
)A.4 B.5 C.6 D.8【答案】D【分析】根據(jù)拋物線焦半徑公式求解即可.【詳解】解:由題知SKIPIF1<0,即SKIPIF1<0,設(shè)SKIPIF1<0,因?yàn)镾KIPIF1<0中點(diǎn)的橫坐標(biāo)為SKIPIF1<0,所以SKIPIF1<0,所以,由拋物線焦半徑公式得SKIPIF1<0故選:D.3.(2023·高三課時(shí)練習(xí))已知橢圓SKIPIF1<0的左準(zhǔn)線為l,左、右焦點(diǎn)分別為SKIPIF1<0、SKIPIF1<0,拋物線SKIPIF1<0的準(zhǔn)線也為l,焦點(diǎn)是SKIPIF1<0,SKIPIF1<0與SKIPIF1<0的一個(gè)交點(diǎn)為點(diǎn)P,則SKIPIF1<0的值等于(
)A.SKIPIF1<0 B.SKIPIF1<0 C.4 D.8【答案】B【分析】由橢圓方程得出SKIPIF1<0,即可得橢圓的離心率,設(shè)SKIPIF1<0到準(zhǔn)線SKIPIF1<0的距離為SKIPIF1<0,由SKIPIF1<0是拋物線上的點(diǎn)得SKIPIF1<0,由SKIPIF1<0是橢圓上的點(diǎn)得SKIPIF1<0,且SKIPIF1<0,從而可求得SKIPIF1<0.【詳解】橢圓SKIPIF1<0中,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,因此左準(zhǔn)線SKIPIF1<0的方程為SKIPIF1<0即SKIPIF1<0,又SKIPIF1<0,設(shè)SKIPIF1<0到準(zhǔn)線SKIPIF1<0的距離為SKIPIF1<0,由SKIPIF1<0是拋物線上的點(diǎn)得SKIPIF1<0,由SKIPIF1<0是橢圓上的點(diǎn)得SKIPIF1<0,且SKIPIF1<0,解得SKIPIF1<0.故選:B.4.(2023·全國·校聯(lián)考模擬預(yù)測)已知拋物線SKIPIF1<0的焦點(diǎn)為SKIPIF1<0,過點(diǎn)SKIPIF1<0的直線SKIPIF1<0交SKIPIF1<0于SKIPIF1<0兩點(diǎn),SKIPIF1<0為坐標(biāo)原點(diǎn),記SKIPIF1<0與SKIPIF1<0的面積分別為SKIPIF1<0和SKIPIF1<0,則SKIPIF1<0的最小值為(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B【分析】設(shè)出直線SKIPIF1<0,聯(lián)立SKIPIF1<0,得到兩根之和,兩根之積,得SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,利用基本不等式即可求出最值.【詳解】由題意得:SKIPIF1<0,設(shè)直線SKIPIF1<0,聯(lián)立SKIPIF1<0得:SKIPIF1<0,設(shè)SKIPIF1<0,不妨令SKIPIF1<0,則SKIPIF1<0,故SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0,當(dāng)且僅當(dāng)SKIPIF1<0,即SKIPIF1<0時(shí),等號(hào)成立.故選:B5.(2022秋·福建寧德·高三校考期末)已知雙曲線SKIPIF1<0的左、右焦點(diǎn)分別為SKIPIF1<0,過SKIPIF1<0的直線l交雙曲線于A,B兩點(diǎn),A,B分別位于第一、第二象限,SKIPIF1<0為等邊三角形,則雙曲線的離心率SKIPIF1<0(
)A.SKIPIF1<0 B.5 C.SKIPIF1<0 D.7【答案】C【分析】設(shè)SKIPIF1<0,由圖形性質(zhì)結(jié)合雙曲線的定義求出SKIPIF1<0,取SKIPIF1<0的中點(diǎn)SKIPIF1<0,利用勾股定理求出SKIPIF1<0,從而得出答案.【詳解】設(shè)題意SKIPIF1<0,設(shè)SKIPIF1<0,則SKIPIF1<0則SKIPIF1<0,由雙曲線的定義可得SKIPIF1<0,所以SKIPIF1<0取SKIPIF1<0的中點(diǎn)SKIPIF1<0,連接SKIPIF1<0,由SKIPIF1<0為等邊三角形,則SKIPIF1<0,且SKIPIF1<0所以SKIPIF1<0,SKIPIF1<0所以SKIPIF1<0,所以SKIPIF1<0故選:C6.(2023秋·江西撫州·高三臨川一中??计谀┮阎p曲線SKIPIF1<0的左、右焦點(diǎn)分別為SKIPIF1<0,SKIPIF1<0,點(diǎn)SKIPIF1<0的坐標(biāo)為SKIPIF1<0,點(diǎn)SKIPIF1<0是雙曲線在第二象限的部分上一點(diǎn),且SKIPIF1<0,SKIPIF1<0,則雙曲線的離心率為(
)A.3 B.2 C.SKIPIF1<0 D.SKIPIF1<0【答案】B【分析】由角平分線的性質(zhì)可得SKIPIF1<0及雙曲線的定義,化簡方程即可求雙曲線的離心率.【詳解】如圖,因?yàn)镾KIPIF1<0,所以SKIPIF1<0,由SKIPIF1<0可得SKIPIF1<0,由雙曲線定義可知SKIPIF1<0,由SKIPIF1<0知:SKIPIF1<0平分SKIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0,整理得:SKIPIF1<0,由SKIPIF1<0,SKIPIF1<0,可化簡為SKIPIF1<0,即SKIPIF1<0,可得SKIPIF1<0,解得SKIPIF1<0或SKIPIF1<0(舍去),故選:B二、多選題7.(2023秋·江蘇揚(yáng)州·高三校聯(lián)考期末)已知非零常數(shù)a,若點(diǎn)A的坐標(biāo)為SKIPIF1<0,點(diǎn)B的坐標(biāo)為SKIPIF1<0,直線SKIPIF1<0與SKIPIF1<0相交于點(diǎn)P,且它們的斜率之積為非零常數(shù)SKIPIF1<0,那么下列說法中正確的有(
).A.當(dāng)SKIPIF1<0時(shí),點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是焦點(diǎn)在x軸上的橢圓B.當(dāng)SKIPIF1<0時(shí),點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是圓心在原點(diǎn)的圓C.當(dāng)SKIPIF1<0時(shí),點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是焦點(diǎn)在y軸上的橢圓D.當(dāng)SKIPIF1<0時(shí),點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是焦點(diǎn)在x軸上的雙曲線【答案】BD【分析】設(shè)點(diǎn)P的坐標(biāo)為SKIPIF1<0,根據(jù)已知條件,求得軌跡方程,然后根據(jù)平方項(xiàng)的系數(shù)的正負(fù),同號(hào)異號(hào),同號(hào)時(shí)相等與否分類討論即可判斷.【詳解】設(shè)點(diǎn)P的坐標(biāo)為SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0SKIPIF1<0.當(dāng)SKIPIF1<0時(shí),SKIPIF1<0SKIPIF1<0,即SKIPIF1<0SKIPIF1<0,所以點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是焦點(diǎn)在y軸上的橢圓,故A錯(cuò)誤.當(dāng)SKIPIF1<0時(shí),SKIPIF1<0SKIPIF1<0,所以點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是圓心在原點(diǎn)的圓,故B正確.當(dāng)SKIPIF1<0時(shí),SKIPIF1<0SKIPIF1<0,所以點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是焦點(diǎn)在x軸上的橢圓,故C錯(cuò)誤.當(dāng)SKIPIF1<0時(shí),SKIPIF1<0SKIPIF1<0,所以點(diǎn)P的軌跡加上A,B兩點(diǎn)所形成的曲線是焦點(diǎn)在x軸上的雙曲線,故D正確.故選:BD三、填空題8.(2023·高三課時(shí)練習(xí))已知雙曲線E:SKIPIF1<0的左、右焦點(diǎn)分別為SKIPIF1<0、SKIPIF1<0,點(diǎn)P在雙曲線E上,且SKIPIF1<0,則SKIPIF1<0=______.【答案】9【分析】根據(jù)雙曲線的定義即可求得SKIPIF1<0.【詳解】因?yàn)殡p曲線ESKIPIF1<0,所以SKIPIF1<0,則SKIPIF1<0,又因?yàn)镾KIPIF1<0,則SKIPIF1<0,即SKIPIF1<0或SKIPIF1<0,又SKIPIF1<0,故SKIPIF1<0.故答案為:9.9.(2022·全國·統(tǒng)考高考真題)記雙曲線SKIPIF1<0的離心率為e,寫出滿足條件“直線SKIPIF1<0與C無公共點(diǎn)”的e的一個(gè)值______________.【答案】2(滿足SKIPIF1<0皆可)【分析】根據(jù)題干信息,只需雙曲線漸近線SKIPIF1<0中SKIPIF1<0即可求得滿足要求的e值.【詳解】解:SKIPIF1<0,所以C的漸近線方程為SKIPIF1<0,結(jié)合漸近線的特點(diǎn),只需SKIPIF1<0,即SKIPIF1<0,可滿足條件“直線SKIPIF1<0與C無公共點(diǎn)”所以SKIPIF1<0,又因?yàn)镾KIPIF1<0,所以SKIPIF1<0,故答案為:2(滿足SKIPIF1<0皆可)10.(2022·全國·統(tǒng)考高考真題)若雙曲線SKIPIF1<0的漸近線與圓SKIPIF1<0相切,則SKIPIF1<0_________.【答案】SKIPIF1<0【分析】首先求出雙曲線的漸近線方程,再將圓的方程化為標(biāo)準(zhǔn)式,即可得到圓心坐標(biāo)與半徑,依題意圓心到直線的距離等于圓的半徑,即可得到方程,解得即可.【詳解】解:雙曲線SKIPIF1<0的漸近線為SKIPIF1<0,即SKIPIF1<0,不妨取SKIPIF1<0,圓SKIPIF1<0,即SKIPIF1<0,所以圓心為SKIPIF1<0,半徑SKIPIF1<0,依題意圓心SKIPIF1<0到漸近線SKIPIF1<0的距離SKIPIF1<0,解得SKIPIF1<0或SKIPIF1<0(舍去).故答案為:SKIPIF1<0.【沖刺提升】一、單選題1.(2023秋·江西·高三校聯(lián)考期末)如圖,已知拋物線E:SKIPIF1<0的焦點(diǎn)為F,過F且斜率為1的直線交E于A,B兩點(diǎn),線段AB的中點(diǎn)為M,其垂直平分線交x軸于點(diǎn)C,SKIPIF1<0軸于點(diǎn)N.若四邊形SKIPIF1<0的面積等于8,則E的方程為(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B【分析】根據(jù)SKIPIF1<0求出SKIPIF1<0的坐標(biāo),然后得SKIPIF1<0的方程,令SKIPIF1<0,得SKIPIF1<0的坐標(biāo),利用直角梯形的面積求出SKIPIF1<0,可得拋物線方程.【詳解】易知SKIPIF1<0,直線AB的方程為SKIPIF1<0,四邊形OCMN為直角梯形,且SKIPIF1<0.設(shè)SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,SKIPIF1<0,∴SKIPIF1<0.所以MC直線方程為SKIPIF1<0,∴令SKIPIF1<0,∴SKIPIF1<0,∴SKIPIF1<0.所以四邊形OCMN的面積為SKIPIF1<0,∴SKIPIF1<0.故拋物線E的方程為SKIPIF1<0.故選:B.2.(2022秋·福建寧德·高三??计谀┰O(shè)橢圓SKIPIF1<0的左、右焦點(diǎn)分別為SKIPIF1<0,SKIPIF1<0,點(diǎn)SKIPIF1<0,SKIPIF1<0在SKIPIF1<0上(SKIPIF1<0位于第一象限),且點(diǎn)SKIPIF1<0,SKIPIF1<0關(guān)于原點(diǎn)對稱,若SKIPIF1<0,SKIPIF1<0,則SKIPIF1<0的離心率為(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】C【分析】由題知四邊形SKIPIF1<0是矩形,其中SKIPIF1<0,進(jìn)而根據(jù)SKIPIF1<0,結(jié)合勾股定理與橢圓定義求解即可.【詳解】解:因?yàn)镾KIPIF1<0,點(diǎn)SKIPIF1<0,SKIPIF1<0關(guān)于原點(diǎn)對稱所以,線段SKIPIF1<0互相平分,且相等,所以四邊形SKIPIF1<0是矩形,其中SKIPIF1<0,設(shè)SKIPIF1<0,所以,SKIPIF1<0,所以橢圓離心率為SKIPIF1<0故選:C3.(2023秋·貴州銅仁·高三統(tǒng)考期末)已知SKIPIF1<0是雙曲線SKIPIF1<0的左、右焦點(diǎn),過SKIPIF1<0的直線l與雙曲線的左支交于點(diǎn)A,與右支交于點(diǎn)B,若SKIPIF1<0,且雙曲線的離心率為SKIPIF1<0,則(
)A.SKIPIF1<0 B.SKIPIF1<0 C.SKIPIF1<0 D.SKIPIF1<0【答案】B【分析】由已知條件和雙曲線的定義可得SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,SKIPIF1<0,由SKIPIF1<0,應(yīng)用余弦定理,化簡可得SKIPIF1<0【詳解】由雙曲線定義和題設(shè)條件,得SKIPIF1<0,SKIPIF1<0,SKIPIF1<0.如圖所示,因?yàn)镾KIPIF1<0,所以SKIPIF1<0.又由雙曲線定義,得SKIPIF1<0,因?yàn)镾KIPIF1<0,所以SKIPIF1<0.在SKIPIF1<0和SKIPIF1<0中,SKIPIF1<0,有SKIPIF1<0,應(yīng)用余弦定理,得SKIPIF1<0,得SKIPIF1<0,化簡得SKIPIF1<0,所以SKIPIF1<0.故選:B.二、多選題4.(2023秋·河北邯鄲·高三統(tǒng)考期末)已知雙曲線SKIPIF1<0的上、下焦點(diǎn)分別為SKIPIF1<0,點(diǎn)P在雙曲線上且位于x軸上方,則下列結(jié)論正確的是(
)A.線段SKIPIF1<0的最小值為1B.點(diǎn)P到兩漸近線的距離的乘積為SKIPIF1<0C.若SKIPIF1<0為直角三角形,則SKIPIF1<0的面積為5D.SKIPIF1<0的內(nèi)切圓圓心在直線SKIPIF1<0上【答案】ABD【分析】根據(jù)給定條件,求出雙曲線的焦點(diǎn)坐標(biāo)及實(shí)軸長,再結(jié)合雙曲線的范圍、定義計(jì)算判斷ABC;作圖結(jié)合定義求出雙曲線內(nèi)切圓圓心縱坐標(biāo)判斷D作答.【詳解】雙曲線SKIPIF1<0的焦點(diǎn)SKIPIF1<0,實(shí)軸長SKIPIF1<0,設(shè)點(diǎn)SKIPIF1<0,有SKIPIF1<0,對于A,SKIPIF1<0,則SKIPIF1<0,當(dāng)且僅當(dāng)SKIPIF1<0時(shí)取等號(hào),A正確;對于B,雙曲線漸近線SKIPIF1<0,則點(diǎn)P到兩漸近線的距離的乘積為:SKIPIF1<0,B正確;對于C,SKIPIF1<0為直角三角形,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,解得SKIPIF1<0,SKIPIF1<0,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,解得SKIPIF1<0,SKIPIF1<0,C不正確;對于D,如圖,圓C是SKIPIF1<0的內(nèi)切圓,切點(diǎn)分別為SKIPIF1<0,設(shè)點(diǎn)SKIPIF1<0,由雙曲線的定義及圓的切線性質(zhì)得:SKIPIF1<0,解得SKIPIF1<0,而SKIPIF1<0,即直線SKIPIF1<0方程為:SKIPIF1<0,所以SKIPIF1<0的內(nèi)切圓圓心在直線SKIPIF1<0上,D正確.故選:ABD5.(2023秋·山西太原·高三統(tǒng)考期末)已知拋物線SKIPIF1<0的焦點(diǎn)為SKIPIF1<0,過點(diǎn)SKIPIF1<0的直線交SKIPIF1<0于SKIPIF1<0兩個(gè)不同點(diǎn),則下列結(jié)論正確的是(
)A.若點(diǎn)SKIPIF1<0,則SKIPIF1<0的最小值是3B.SKIPIF1<0的最小值是2C.若SKIPIF1<0,則直線SKIPIF1<0的斜率為SKIPIF1<0D.過點(diǎn)SKIPIF1<0分別作拋物線SKIPIF1<0的切線,設(shè)兩切線的交點(diǎn)為SKIPIF1<0,則點(diǎn)SKIPIF1<0的橫坐標(biāo)為SKIPIF1<0【答案】ACD【分析】過點(diǎn)SKIPIF1<0分別作準(zhǔn)線的垂線,垂足分別為SKIPIF1<0,進(jìn)而根據(jù)拋物線的定義判斷A;根據(jù)SKIPIF1<0判斷B;設(shè)直線SKIPIF1<0的方程為SKIPIF1<0,SKIPIF1<0,進(jìn)而聯(lián)立方程,結(jié)合韋達(dá)定理,根據(jù)SKIPIF1<0解方程即可得判斷C;根據(jù)直線與曲線的位置關(guān)系得過點(diǎn)SKIPIF1<0,分別與拋物線SKIPIF1<0相切的直線方程為SKIPIF1<0,SKIPIF1<0,進(jìn)而聯(lián)立方程解得SKIPIF1<0可判斷D.【詳解】解:由題知SKIPIF1<0,SKIPIF1<0,準(zhǔn)線方程為SKIPIF1<0,對于A選項(xiàng),如圖,過點(diǎn)SKIPIF1<0分別作準(zhǔn)線的垂線,垂足分別為SKIPIF1<0,故SKIPIF1<0,故正確;對于B選項(xiàng),設(shè)SKIPIF1<0,故SKIPIF1<0,故錯(cuò)誤;對于C選項(xiàng),當(dāng)直線SKIPIF1<0的斜率不存在時(shí),SKIPIF1<0,不成立;故直線SKIPIF1<0的斜率存在,設(shè)方程為SKIPIF1<0,與拋物線方程聯(lián)立SKIPIF1<0得SKIPIF1<0,所以SKIPIF1<0,因?yàn)镾KIPIF1<0,所以SKIPIF1<0,即SKIPIF1<0,解得SKIPIF1<0,故正確;對于D選項(xiàng),設(shè)過點(diǎn)SKIPIF1<0與拋物線SKIPIF1<0相切的直線方程為SKIPIF1<0,與拋物線方程SKIPIF1<0聯(lián)立得SKIPIF1<0,所以SKIPIF1<0,整理得SKIPIF1<0,所以SKIPIF1<0,故SKIPIF1<0即為SKIPIF1<0,整理得SKIPIF1<0同理得過點(diǎn)SKIPIF1<0與拋物線SKIPIF1<0相切的直線方程為SKIPIF1<0,所以,聯(lián)立方程SKIPIF1<0,解方程得SKIPIF1<0,因?yàn)镾KIPIF1<0,所以SKIPIF1<0所以SKIPIF1<0,即點(diǎn)SKIPIF1<0的橫坐標(biāo)為SKIPIF1<0,故正確.故選:ACD三、填空題6.(2023·高三課時(shí)練習(xí))已知SKIPIF1<0、SKIPIF1<0是橢圓SKIPIF1<0的兩個(gè)焦點(diǎn),P為橢圓C上的一點(diǎn),且SKIPIF1<0,若SKIPIF1<0的面積為9,則b=______.【答案】3【分析】利用三角形SKIPIF1<0的面積列方程,由此求得SKIPIF1<0.【詳解】設(shè)SKIPIF1<0,由于SKIPIF1<0,所以SKIPIF1<0,SKIPIF1<0,所以SKIPIF1<0.故答案為:SKIPIF1<07.(2023·廣西柳州·統(tǒng)考模擬預(yù)測)雙曲線SKIPIF1<0的一條漸近線與曲線SKIPIF1<0交于M、N兩個(gè)不同的點(diǎn),則SKIPIF1<0__________.【答案】SKIPIF1<0##SKIPIF1<0【分析】根據(jù)題意先求出雙曲線SKIPIF1<0的一條漸近線方程,然后與曲線聯(lián)立,求出交點(diǎn)SKIPIF1<0、SKIPIF1<0的坐標(biāo),代入兩點(diǎn)間距離公式即可求解.【詳解】由題意知:雙曲線SKIPIF1<0的漸近線方程為:SKIPIF1<0,不妨取SKIPIF1<0,即SKIPIF1<0,因?yàn)榍€SKIPIF1<0可化為SKIPIF1<0,聯(lián)立方程組SKIPIF1<0,解得:SKIPIF1<0或SKIPIF1<0,取SKIPIF1<0,所以SKIPIF1<0,故答案為:SKIPIF1<0.8.(2023·高三課時(shí)練習(xí))設(shè)平面直角坐標(biāo)系中,O為原點(diǎn),N為動(dòng)點(diǎn),SKIPIF1<0,SKIPIF1<0,過點(diǎn)M作SKIPIF1<0軸于點(diǎn)SKIPIF1<0,過點(diǎn)N作SKIPIF1<0軸于點(diǎn)SKIPIF1<0,M與SKIPIF1<0不重合,N與SKIPIF1<0不重合,設(shè)SKIPIF1<0,則點(diǎn)T的軌跡方程是______.【答案】SKIPIF1<0【分析】設(shè)出點(diǎn)SKIPIF1<0的坐標(biāo),根據(jù)SKIPIF1<0,可以知道點(diǎn)SKIPIF1<0的橫坐標(biāo)和縱坐標(biāo)之間的關(guān)系,SKIPIF1<0可以求出SKIPIF1<0的坐標(biāo),進(jìn)而根據(jù)已知的條件,求出SKIPIF1<0、SKIPIF1<0的坐標(biāo),設(shè)出點(diǎn)SKIPIF1<0的坐標(biāo),通過SKIPIF1<0,可以得到SKIPIF1<0的坐標(biāo)和SKIPIF1<0的坐標(biāo)之間的關(guān)系,再根據(jù)點(diǎn)SKIPIF1<0的橫坐標(biāo)和縱坐標(biāo)之間的關(guān)系,求出點(diǎn)SKIPIF1<0的軌跡方程.【詳解】設(shè)點(diǎn)SKIPIF1<0,因?yàn)镾KIPIF1<0,所以有SKIPIF1<0,因?yàn)镾KIPIF1<0,所以有SKIPIF1<0,由題意可知:SKIPIF1<0,SKIPIF1<0,因?yàn)镾KIPIF1<0與SKIPIF1<0不重合,SKIPIF1<0與SKIPIF1<0不重合,所以SKIPIF1<0且SKIPIF1<0,SKIPIF1<0設(shè)SKIPIF1<0,因?yàn)镾KIPIF1<0,所以有SKIPIF1<0,而SKIPIF1<0,所以SKIPIF1<0,又因?yàn)镾KIPIF1<0且SKIPIF1<0,故答案為:SKIPIF1<0(SKIPIF1<0且SKIPIF1<0)9.(2023秋·海南·高三統(tǒng)考期末)如圖,已知SKIPIF1<0,SKIPIF1<0分別是橢圓SKIPIF1<0的左、右焦點(diǎn),M,N為橢圓上兩點(diǎn),滿足SKIPIF1<0,且SKIPIF1<0,則橢圓C的離心率為________.【答案】SKIPIF1<0【分析】如圖,延長SKIPIF1<0,與橢圓交于點(diǎn)L,連接SKIPIF1<0,設(shè)SKIPIF1<0可得SKIPIF1<0,在SKIPIF1<0中,用余弦定理可得到SKIPIF1<0,繼而得到SKIPIF1<0,即可求解【詳解】設(shè)橢圓的半焦距為SKIPIF1<0,如圖,延長SKIPIF1<0,與橢圓交于點(diǎn)L,連接SKIPIF1<0,由SKIPIF1<0,所以根據(jù)對稱性可知,SKIPIF1<0,設(shè)SKIPIF1<0,則SKIPIF1<0,SKIPIF1<0,從而SKIPIF1<0,故SKIPIF1<0,在SKIPIF1<0中,SKIPIF1<0,所以SKIPIF1<0,在SKIPIF1<0中,SKIPIF1<0,即SKIPIF1<0,所以SKIPIF1<0,所以SKIPIF1<0,所以離心率SKIPIF1<0,故答案為:SKIPIF1<010.(2023秋·河北邯鄲·高三統(tǒng)考期末)已知拋物線SKIPIF1<0的焦點(diǎn)為F,若SKIPIF1<0在拋物線C上,且滿足SKIPIF1<0,則SKIPIF1<0的最小值為______.【答案】9【分析】設(shè)直線SKIPIF1<0的傾斜角為SKIPIF1<0,用SKIPIF1<0表示出SKIPIF1<0,由此建立關(guān)于SKIPIF1<0的函數(shù),再換元利用導(dǎo)數(shù)求解作答.【詳解】拋物線SKIPIF1<0的焦點(diǎn)為SKIPIF1<0,依題意,不妨設(shè)直線SKIPIF1<0的傾斜角為SKIPIF1<0,且SKIPIF1<0,由拋物線定義得:SKIPIF1<0,即SKIPIF1<0,同理SKIPIF1<0,SKIPIF1<0SKIPIF1<0SKIPIF1<0,因此SKIPIF1<0,令SKIPIF1<0,SKIPIF1<0,令SKIPIF1<0,SKIPIF1<0,由SKIPIF1<0得SKIPIF1<0或SKIPIF1<0,由SKIPIF1<0得SKIPIF1<0,因此函數(shù)SKIPIF1<0在SKIPIF1<0上單調(diào)遞減,在SKIPIF1<0上單調(diào)遞增,當(dāng)SKIPIF1<0時(shí),SKIPIF1<0,此時(shí)SKIPIF1<0,于是得SKIPIF1<0,所以當(dāng)SKIPIF1<0時(shí),SKIPIF1<0取得最小值9.故答案為:9【點(diǎn)睛】方法點(diǎn)睛:圓錐曲線中最值或范圍問題的常見解法:(1)幾何法,若題目的條件和結(jié)論能明顯體現(xiàn)幾何特征和意義,則考慮利用幾何法來解決;(2)代數(shù)法,若題目的條件和結(jié)論能體現(xiàn)某種明確的函數(shù)關(guān)系,則可首先建立目標(biāo)函數(shù),再求這個(gè)函數(shù)的最值或范圍.四、解答題11.(2023·高三課時(shí)練習(xí))已知SKIPIF1<0、SKIPIF1<0是雙曲線SKIPIF1<0的左、右焦點(diǎn).(1)求證:雙曲線C上任意一點(diǎn)M到雙曲線兩條漸近線的距離之積為常數(shù);(2)過SKIPIF1<0且垂直于x軸的直線交C于P、Q兩點(diǎn),SKIPIF1<0,且C過點(diǎn)(1,0),求雙曲線C的方程.【答案】(1)證明見解析;(2)SKIPIF1<0.【分析】(1)設(shè)
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