7£®½«Ô²C1£ºx2+y2=4ÉÏÿһµãµÄ×Ý×ø±ê±£³Ö²»±ä£¬ºá×ø±ê±äΪԭÀ´µÄ$\sqrt{5}$±¶µÃµ½ÇúÏßC2£®
£¨1£©Ð´³öC2µÄ²ÎÊý·½³Ì£»
£¨2£©ÒÑÖªF£¨-4£¬0£©£¬Ö±ÏßlµÄ²ÎÊý·½³ÌΪ$\begin{array}{l}\left\{\begin{array}{l}x=-4+\sqrt{2}t\\ y=\sqrt{2}t\end{array}\right.\end{array}$£¨tΪ²ÎÊý£©£¬Ö±Ïßl½»ÇúÏßC2ÓÚA£¬BÁ½µã£¬Çó|AF|+|BF|

·ÖÎö £¨1£©Çó³öÇúÏßC2µÄÆÕͨ·½³Ì£¬¼´¿Éд³öC2µÄ²ÎÊý·½³Ì£»
£¨2£©½«Ö±ÏߵIJÎÊý·½³Ì±äΪ$\left\{\begin{array}{l}{x=-4+\frac{\sqrt{2}}{2}t¡ä}\\{y=\frac{\sqrt{2}}{2}t¡ä}\end{array}\right.$£¨t¡äΪ²ÎÊý£©´úÈëx2+5y2=20£¬»¯¼òµÃ$3t{¡ä}^{2}-4\sqrt{2}t¡ä-4=0$£¬ÀûÓòÎÊýµÄ¼¸ºÎÒâÒ壬¼´¿ÉÇó|AF|+|BF|£®

½â´ð ½â£º£¨1£©ÉèÔ²C1ÉÏÈÎÒâÒ»µãP£¨x£¬y£©£¬ÇúÏßC2ÉÏÈÎÒâÒ»µãP'£¨x'£¬y'£©£¬
ÔòÓÉÌâÒâµÃ$\left\{\begin{array}{l}x'=\sqrt{5}x\\ y'=y\end{array}\right.$£¬¡à$\left\{\begin{array}{l}x=\frac{1}{{\sqrt{5}}}x'\\ y=y'\end{array}\right.$´úÈëC1·½³Ìx2+y2=4£¬¿ÉµÃ$\frac{{{{x'}^2}}}{20}+\frac{{{{y'}^2}}}{4}=1$£¬
¼´ÇúÏßC2µÄ²ÎÊý·½³ÌΪ$\left\{\begin{array}{l}x=2\sqrt{5}cos¦È\\ y=2sin¦È\end{array}\right.£¨¦ÈΪ²ÎÊý£©$
£¨2£©½«Ö±ÏߵIJÎÊý·½³Ì±äΪ$\left\{\begin{array}{l}{x=-4+\frac{\sqrt{2}}{2}t¡ä}\\{y=\frac{\sqrt{2}}{2}t¡ä}\end{array}\right.$£¨t¡äΪ²ÎÊý£©´úÈëx2+5y2=20£¬
»¯¼òµÃ$3t{¡ä}^{2}-4\sqrt{2}t¡ä-4=0$£¬Éè·½³ÌµÄÁ½¸öʵ¸ùΪt'1£¬t'2£¬¡àt'1+t'2=$\frac{4\sqrt{2}}{3}$£¬t'1t'2=-$\frac{4}{3}$£¬
Ôò|AF|+|BF|=|t'1-t'2|=$\sqrt{\frac{32}{9}+4¡Á\frac{4}{3}}$=$\frac{4\sqrt{5}}{3}$£®

µãÆÀ ±¾Ì⿼²é²ÎÊý·½³Ì£¬¿¼²é²ÎÊýµÄ¼¸ºÎÒâÒåµÄÔËÓã¬ÊôÓÚÖеµÌ⣮

Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

17£®¸´Æ½ÃæÄÚ£¬ÒÑ֪ƽÐÐËıßÐÎÈýµã¶ÔÓ¦µÄ¸´ÊýÊÇ-2£¬i£¬-1+3i£¬ÇóµÚËĵã¶ÔÓ¦µÄ¸´Êý£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

18£®º¯Êýf£¨x£©ÔÚ¶¨ÒåÓòRÄڿɵ¼£¬Èôf£¨x+1£©ÊÇżº¯Êý£¬ÇÒ£¨x-1£©f'£¨x£©£¼0£¬Éèa=f£¨0£©£¬$b=f£¨\frac{1}{2}£©$£¬c=f£¨3£©£¬Ôò£¨¡¡¡¡£©
A£®a£¼b£¼cB£®c£¼b£¼aC£®c£¼a£¼bD£®b£¼c£¼a

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

15£®´Ó0£¬1£¬2£¬3£¬4Îå¸öÊýÖÐÑ¡ËĸöÊý×Ö£¬×é³ÉÎÞÖØ¸´Êý×ÖµÄËÄλÊý£¬ÆäÖÐżÊýµÄ¸öÊýΪ£¨¡¡¡¡£©
A£®36B£®60C£®72D£®96

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

2£®Èçͼ£¬ËÄÀâ×¶P-ABCDÖУ¬µ×ÃæABCDÊÇÌÝÐΣ¬¡ÏADC=¡ÏBAD=90¡ãÇÒAB=AD=PD=2CD=2£¬PD¡ÍÆ½ÃæABCD£¬EÊÇPAÖе㣮
£¨1£©ÇóÖ¤£ºDE¡ÍPB
£¨2£©ÇóÆ½ÃæPADºÍÆ½ÃæPBCËù³ÉÈñ¶þÃæ½ÇµÄÓàÏÒÖµ£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÌî¿ÕÌâ

12£®Éè$\overrightarrow a$£¬$\overrightarrow b$ÊÇÁ½¸ö²»¹²ÏßµÄÏòÁ¿£¬$\overrightarrow{AB}=2\overrightarrow a+k\overrightarrow b$£¬$\overrightarrow{BC}=\overrightarrow a+\overrightarrow b$£¬$\overrightarrow{CD}=\overrightarrow a-2\overrightarrow b$£¬ÈôA£¬B£¬DÈýµã¹²Ïߣ¬ÔòʵÊýkµÄֵΪ-1£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

19£®Ëæ»ú²É·Ã50Ãû¹ÛÖÚ¶ÔijµçÊÓ½ÚÄ¿µÄÂúÒâ¶È£¬µÃµ½ÈçÏÂÁÐÁª±í£ºµ¥Î»£ºÈË
ÂúÒâ²»ÂúÒâºÏ¼Æ
ÄÐ102030
Ů15520
ºÏ¼Æ252550
¸½±íºÍ¹«Ê½ÈçÏ£º
P£¨K2¡Ýk£©0.1000.0500.0100.001
k2.7063.8416.63510.828
K2=$\frac{n£¨ad-bc£©^{2}}{£¨a+b£©£¨c+d£©£¨a+c£©£¨b+d£©}$£¬ÆäÖÐn=a+b+c+dΪÑù±¾ÈÝÁ¿£®¸ù¾ÝÒÔÉÏÊý¾Ý¿ÉÖª£¨¡¡¡¡£©
A£®ÓÐ95%µÄ°ÑÎÕÈÏΪ¶ÔµçÊÓ½ÚÄ¿µÄÂúÒâ¶ÈÓëÐÔ±ðÎÞ¹Ø
B£®ÓÐ99%µÄ°ÑÎÕÈÏΪ¶ÔµçÊÓ½ÚÄ¿µÄÂúÒâ¶ÈÓëÐÔ±ðÎÞ¹Ø
C£®ÓÐ99%µÄ°ÑÎÕÈÏΪ¶ÔµçÊÓ½ÚÄ¿µÄÂúÒâ¶ÈÓëÐÔ±ðÓйØ
D£®ÓÐ95%µÄ°ÑÎÕÈÏΪ¶ÔµçÊÓ½ÚÄ¿µÄÂúÒâ¶ÈÓëÐÔ±ðÓйØ

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

16£®ÒÑÖª¡÷ABCµÄÈý¸ö¶¥µãA¡¢B¡¢C¼°Æ½ÃæÄÚÒ»µãP£¬Èô$\overrightarrow{PA}+\overrightarrow{PB}+\overrightarrow{PC}=\overrightarrow{AC}$£¬ÔòµãPÔÚ£¨¡¡¡¡£©
A£®¡÷ABCµÄÄÚ²¿B£®¡÷ABCµÄÍⲿC£®PÔÚÏß¶ÎACÉÏD£®PÔÚÏß¶ÎABÉÏ

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÌî¿ÕÌâ

17£®ÈôÖ±Ïߣ¨m+2£©x+3y+3=0ÓëÖ±Ïßx+£¨2m-1£©y+m=0ƽÐУ¬ÔòʵÊým=$-\frac{5}{2}$£®

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸